Independent Factors Contributing to Daytime and Nighttime Asthmatic Cough Refractory to Inhaled Corticosteroids.

BACKGROUND: Cough is a common feature of asthma, which is often resistant to inhaled corticosteroids (ICSs). The pathophysiology of this refractoriness may differ between daytime and nighttime asthmatic cough. We sought to identify factors contributing to ICS-refractory daytime and nighttime asthmatic cough. METHODS: Sixty-seven patients with asthma presenting solely or predominantly with chronic cough were prospectively enrolled from April 2012 to December 2014. At baseline and 12 weeks after ICS treatment, the capsaicin cough threshold (C2, C5) and methacholine airway sensitivity and reactivity were examined. A visual analog scale (VAS) and numeric scores were used to evaluate daytime and nighttime cough symptoms separately. The Japanese version of the Leicester Cough Questionnaire was also completed. When either the VAS or numeric scores showed an improvement of ≥50% or ≥2 points, patients were considered responders to ICS treatment. RESULTS: Fifty-five patients were eligible for evaluation. Subjective cough indices improved significantly at 12 weeks after ICS treatment (P<.001). Multivariate analysis revealed that lower C2 significantly contributed to residual daytime cough (P=.04). Meanwhile, methacholine hyperreactivity and lower IgE levels were predictors of the nighttime residual cough (P=.002 and P=.03, respectively). CONCLUSIONS: Heightened cough reflex sensitivity is an independent factor of daytime asthmatic cough that is refractory to ICSs. In contrast, airway hyperreactivity and less atopic status contribute to ICS-refractory nighttime cough.

IL4Rα and ADAM33 as genetic markers in asthma exacerbations and type-2 inflammatory endotype.

BACKGROUND: Genetic markers of susceptibility to asthma exacerbations in adults remain unclear. OBJECTIVE: To identify genetic markers of asthma exacerbations, particularly in patients with type-2 inflammatory endotype. METHODS: In this observational study of patients enrolled in the Kinki Hokuriku Airway disease Conference multicenter study, frequency of exacerbations requiring systemic corticosteroids during 2 years after enrolment and associated risk factors was determined. For genetic marker analysis, interleukin-4 receptor α (IL4RA) rs8832 and a disintegrin and metalloprotease 33 (ADAM33) S_2 (rs528557), T_1 (rs2280091), T_2 (rs2280090), and V_4 (rs2787094) variants were included. Elevated serum periostin levels at enrolment (≥95 ng/mL, defined as type-2 inflammatory endotype) were considered in the analysis. RESULTS: Among 217 patients who were successfully followed up for 2 years after enrolment, 60 patients showed at least one asthma exacerbation during the 2 years. Airflow limitation (%FEV1 <80%) and recent exacerbations but not genetic variants were identified as risk markers of exacerbations. A total of 27 patients showed type-2 inflammatory endotype (serum periostin ≥95 ng/mL at enrolment) and subsequent exacerbations; risk factors in these patients were airflow limitation (odds ratio, 6.51; 95% confidence interval (CI): 2.37-18.6; P=.0003), GG genotype of IL4RA rs8832 (odds ratio, 4.01; 95% CI: 1.47-11.0; P=.007), and A allele of ADAM33 T_2 (odds ratio, 2.81; 95% CI: 1.05-7.67; P=.04) by multivariate analysis. In addition, GG genotype of IL4RA rs8832 was associated with type-2 endotype, whereas A allele of ADAM33 T_2 was associated with mixed type of eosinophilic/type-2 and neutrophilic inflammations. CONCLUSIONS AND CLINICAL RELEVANCE: IL4RA and ADAM33 variants may be risk markers of asthma exacerbations in type-2 inflammatory endotype. Precise endotyping may facilitate the identification of genetic risk markers of asthma exacerbations.

Mouth breathing, another risk factor for asthma: the Nagahama Study.

BACKGROUND: Allergic rhinitis, a known risk factor for asthma onset, often accompanies mouth breathing. Mouth breathing may bypass the protective function of the nose and is anecdotally considered to increase asthma morbidity. However, there is no epidemiological evidence that mouth breathing is independently associated with asthma morbidity and sensitization to allergens. In this study, we aimed to clarify the association between mouth breathing and asthma morbidity and allergic/eosinophilic inflammation, while considering the effect of allergic rhinitis. METHODS: This community-based cohort study, the Nagahama Study, contained a self-reporting questionnaire on mouth breathing and medical history, blood tests, and pulmonary function testing. We enrolled 9804 general citizens of Nagahama City in the Shiga Prefecture, Japan. RESULTS: Mouth breathing was reported by 17% of the population and was independently associated with asthma morbidity. The odds ratio for asthma morbidity was 1.85 (95% CI, 1.27-2.62) and 2.20 (95% CI, 1.72-2.80) in subjects with mouth breathing alone and allergic rhinitis alone, which additively increased to 4.09 (95% CI, 3.01-5.52) when mouth breathing and allergic rhinitis coexisted. Mouth breathing in nonasthmatics was a risk for house dust mite sensitization, higher blood eosinophil counts, and lower pulmonary function after adjusting for allergic rhinitis. CONCLUSION: Mouth breathing may increase asthma morbidity, potentially through increased sensitization to inhaled allergens, which highlights the risk of mouth-bypass breathing in the 'one airway, one disease' concept. The risk of mouth breathing should be well recognized in subjects with allergic rhinitis and in the general population.

GLCCI1 variant accelerates pulmonary function decline in patients with asthma receiving inhaled corticosteroids.

BACKGROUND: In steroid-naive patients with asthma, several gene variants are associated with a short-term response to inhaled corticosteroid (ICS) treatment; this has mostly been observed in Caucasians. However, not many studies have been conducted for other ethnicities. Here, we aimed to determine the relationship between the annual decline in forced expiratory flow volume in one second (FEV1 ) and the variant of the glucocorticoid-induced transcript 1 gene (GLCCI1) in Japanese patients with asthma receiving long-term ICS treatment, taking into account the effect of high serum periostin levels, a known association factor of pulmonary function decline and a marker of refractory eosinophilic/Th2 inflammation. METHODS: In this study, 224 patients with asthma receiving ICS treatment for at least 4 years were enrolled. The effects of single-nucleotide polymorphisms (SNPs) in GLCCI1, stress-induced phosphoprotein 1 (STIP1), and T gene on the decline in FEV1 of 30 ml/year or greater were determined. RESULTS: Besides the known contributing factors, that is, the most intensive treatment step, ex-smoking, and high serum periostin levels (≥95 ng/ml), the GG genotype of GLCCI1 rs37973, and not other SNPs, was independently associated with a decline in FEV1 of 30 ml/year or greater. When patients were stratified according to their serum periostin levels, the GG genotype of rs37973 was significantly associated with blood eosinophilia (≥250/µl) in the high serum periostin group. CONCLUSIONS: A GLCCI1 variant is a risk factor of pulmonary function decline in Japanese patients with asthma receiving long-term ICS treatment. Thus, GLCCI1 may be associated with response to ICS across ethnicities.

Carbonyl stress: increased carbonyl modification of tissue and cellular proteins in uremia.

Advanced glycation end-products (AGEs) are formed during non enzymatic glycation and oxidation (glycoxidation) reactions. This process is accelerated in diabetics owing to hyperglycemia, and it has been implicated in the pathogenesis of diabetic complications. Surprisingly, AGEs increase in normoglycemic uremic patients to a much greater extent than in diabetics. AGE accumulation in uremia cannot be attributed to hyperglycemia nor simply to a decreased removal by glomerular filtration. Recently gathered evidence has suggested that, in uremia, the increased carbonyl compounds derived from carbohydrates and lipids modify proteins not only by glycoxidation reaction but also by lipoxidation reaction ("carbonyl stress"). Carbonyl stress has been implicated in the pathogenesis of long-term uremic complications such as dialysis-related amyloidosis. With regard to continuous ambulatory peritoneal dialysis (CAPD), the peritoneal cavity appears to be in a state of severe overload of carbonyl compounds derived from CAPD solution containing high glucose, from heat sterilization of the solution, and from uremic circulation. Carbonyl stress might modify not only peritoneal matrix proteins and alter their structures, but also react with mesothelial and endothelial cell surface proteins and initiate a range of inflammatory responses. Carbonyl stress might therefore contribute to the development of peritoneal sclerosis in patients with long-term CAPD.

[Protective effect by piperacillin against renal impairment caused by amikacin].

This study is aimed to demonstrate that renal impairment caused by administration of amikacin (AMK) alone can be lessened by co-administration of piperacillin (PIPC). The patients in the present study were divided into three groups. In "group P" and "group A", PIPC alone and AMK alone were administered, respectively. In "group P+A", PIPC and AMK were co-administered. Dosage of AMK was individualized based upon the therapeutic drug monitoring method, and that of PIPC was adjusted depending upon the creatinine clearance of a patient. In group A, urinary concentrations of beta 2-microglobulin and lysozyme, and urinary excretion of beta 2-microglobulin, lysozyme and gamma-GTP per day were significantly higher (p less than 0.05) than those in group P. These differences were not observed, however, between group P and group P+A. The trough value of AMK, 11 days after AMK administration, was significantly higher in group A (p less than 0.05) than that in group P+A. Incidence of renal impairment, as judged from urinary excretion of beta 2-microglobulin per day and urinary lysozyme concentration, was significantly higher in group A (p less than 0.05) than that in group P+A. These findings indicate that co-administration of PIPC with AMK can lessen the renal impairment caused by administration of AMK alone.

Independent factors contributing to daytime and nighttime asthmatic cough refractory to inhaled corticosteroids

Background: Cough is a common feature of asthma, which is often resistant to inhaled corticosteroids (ICSs). The pathophysiology of this refractoriness may differ between daytime and nighttime asthmatic cough. We sought to identify factors contributing to ICS-refractory daytime and nighttime asthmatic cough. Methods: Sixty-seven patients with asthma presenting solely or predominantly with chronic cough were prospectively enrolled from April 2012 to December 2014. At baseline and 12 weeks after ICS treatment, the capsaicin cough threshold (C2, C5) and methacholine airway sensitivity and reactivity were examined. A visual analog scale (VAS) and numeric scores were used to evaluate daytime and nighttime cough symptoms separately. The Japanese version of the Leicester Cough Questionnaire was also completed. When either the VAS or numeric scores showed an improvement of ≥50% or ≥2 points, patients were considered responders to ICS treatment.Results: Fifty-five patients were eligible for evaluation. Subjective cough indices improved significantly at 12 weeks after ICS treatment (P<.001). Multivariate analysis revealed that lower C2 significantly contributed to residual daytime cough (P=.04). Meanwhile, methacholine hyperreactivity and lower IgE levels were predictors of the nighttime residual cough (P=.002 and P=.03, respectively). Conclusions: Heightened cough reflex sensitivity is an independent factor of daytime asthmatic cough that is refractory to ICSs. In contrast, airway hyperreactivity and less atopic status contribute to ICS-refractory nighttime cough

Introducción: La tos es una característica común del asma, que a menudo es resistente a los corticosteroides inhalados (ICS). La fisiopatología involucrada en dicha refractariedad al tratamiento esteroideo puede ser diferente entre la tos asmática diurna y nocturna. El objetivo del estudio es intentar identificar los factores que contribuyen a esta insensibilidad al tratamiento en la tos asmática diurna y nocturna. Métodos: Sesenta y siete pacientes, con asma solo o con tos crónica, se inscribieron prospectivamente desde abril de 2012 a diciembre de 2014. Al inicio del estudio y 12 semanas después del tratamiento con ICS, se examinaron el umbral de tos frente a capsaicina (C2, C5) y la sensibilidad y reactividad de las vías respiratorias a la metacolina. Se usaron escalas analógicas visuales (VAS) y puntajes numéricos para evaluar los síntomas de tos diurna y nocturna de forma separada. La versión japonesa del Leicester Cough Questionnaire también se completó. Cuando las VAS o los puntajes numéricos mostraron una mejoría de ≥50% o ≥2 puntos, los pacientes se consideraron respondedores al tratamiento con ICS. Resultados: Cincuenta y cinco pacientes completaron adecuadamente toda la evaluación. Los índices subjetivos de tos mejoraron significativamente a las 12 semanas después del tratamiento con ICS (p <0,001). El análisis multivariante reveló que una C2 más baja contribuía significativamente a la tos diurna residual (p = 0,04). Por otra parte, la hiperreactividad a la metacolina y los niveles más bajos de IgE fueron predictores de la tos residual nocturna (p = 0,002 y p = 0,03, respectivamente).Conclusiones: La sensibilidad aumentada a la tos es un factor independiente de la tos asmática diurna refractaria a los corticoides. Por el contrario, la hiperreactividad de las vías respiratorias y la ausencia de atopia contribuyen a la tos nocturna refractaria a los ICS

Thiazolidinediones provide better renoprotection than insulin in an obese, hypertensive type II diabetic rat model.

Hyperinsulinemia has been implicated in the development of diabetic nephropathy. In the present study we compared the renoprotective effects of the thiazolidinedione, pioglitazone (PGZ), to that of insulin in a hypertensive, obese, type II diabetic rat model. PGZ aggravated obesity and gave less glycemic control than insulin. However, renoprotection was markedly better with PZG compared to insulin as shown by lower proteinuria, improved renal function, and less histological evidence of diabetic glomerular and tubulointerstitial lesions. PZG and insulin both reduced renal accumulation of pentosidine and oxidative stress to a similar extent. In contrast, PGZ but not insulin suppressed enhanced transforming growth factor-beta (TGF-beta) expression. We further confirmed in cultured rat proximal tubular cells that insulin enhanced TGF-beta mRNA expression and protein production. Our results identify hyperinsulinemia and the attendant increase of TGF-beta expression as potential therapeutic targets in diabetes independent of glycemic control. This confirms prior clinical evidence that PZG provides renoprotection in obese, diabetic patients with nephropathy.

Implication of altered redox regulation by antioxidant enzymes in the increased plasma pentosidine, an advanced glycation end product, in uremia.

Pentosidine is an advanced glycation end product (AGE) formed during Maillard or browning reaction by non-enzymatic glycation and oxidation (glycoxidation). Recent studies demonstrated the increased plasma pentosidine levels not only in diabetic patients with hyperglycemia but also in normoglycemic uremic patients. The mechanism of increased glycoxidation reaction in uremia, however, remains unknown. As superoxide dismutases (SODs) and glutathione peroxidase (GPx) are antioxidant enzymes involved in the metabolism of H2O2 which accelerates the glycoxidation reaction, we measured their activities by enzymatic assays in the plasma of normal and non-diabetic hemodialysis patients and examined a link between redox regulation by antioxidant enzymes and glycoxidation reaction. The activities of GPx were significantly lower in the plasma of hemodialysis patients than in normal subjects, whereas those of SODs were higher in the former than in the latter. As plasma SODs comprise three isozymes, i.e., Cu/Zn-SOD, Mn-SOD, and extracellular (EC)-SOD, we determined the levels of each SOD isozyme by ELISAs. The plasma concentrations of Cu/Zn-SOD and EC-SOD were significantly higher in hemodialysis patients than in normal subjects, whereas those of Mn-SOD did not differ between the two groups. It is of note that GPx activities correlated inversely with pentosidine in the plasma of hemodialysis patients (r2 = 0.262, P < 0.01). There was no significant correlation between total SOD activities and pentosidine levels in the plasma of hemodialysis patients, but, among the three SOD isozymes, the plasma EC-SOD levels correlated with the levels of pentosidine in hemodialysis patients (r2 = 0.286, P < 0.05). As decreased GPx and increased SOD activities result in the increased H2O2 generation, which accelerates the glycoxidation of protein, these data suggest a link of altered redox regulation by antioxidant enzymes to increased glycoxidation reaction in the uremic plasma. This paper provides the first time evidence for the possible involvement of enzymatic redox regulation in the non-enzymatic glycoxidation reaction in vivo.

Nitric oxide inhibits the formation of advanced glycation end products.

BACKGROUND: Advanced glycation end products (AGEs) are elevated in renal failure and have been implicated in the pathogenesis of several uremic complications. Their formation is closely associated with oxidative stress. The recent observation that nitric oxide (NO) has an antioxidant effect led us to examine the possible role of NO in the generation of AGEs. METHODS: We examined the effect of NO donors, 2, 2'-(hydroxynitrosohydrazono)bis-ethanamine (NOC18) and S-nitroso-N-acetyl-DL-penicillamine (SNAP), on the in vitro formation of pentosidine, which was used as a surrogate marker for AGEs. Bovine serum albumin was incubated under air at 37 degrees C in a medium containing either several AGE precursors or uremic plasma. To elucidate further the mechanism of the NO effect on AGE formation, we examined the generation of free radicals and carbonyls in pentose-driven pentosidine formation. RESULTS: NO donors significantly inhibit the formation of pentosidine in a dose-dependent manner. The effect is abolished by the addition of a NO scavenging agent, 2-(4-carboxyphenyl)-4,4,5, 5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO). The inhibitory effect results from NO but not from the NO donor molecule. It is best explained by the ability of NO to scavenge carbon-centered radicals, hydroxyl radical, and carbonyl compounds. CONCLUSIONS: NO inhibits pentosidine formation by scavenging free radicals and by inhibiting carbonyl compound formation. NO might be implicated in the atherogenic and inflammatory effects of AGEs: Reduced NO production and increased oxidative stress associated with atherosclerotic lesions may accelerate AGE formation and, thus, exacerbate endothelial dysfunction and accelerate the development of atherosclerosis in uremia.

A sensitive and specific ELISA for plasma pentosidine.

BACKGROUND: Advanced glycation end products are formed by non-enzymatic glycation and oxidation reaction. Pentosidine is a well-known and characterized structure among them, and has been implicated in the pathogenesis of complications associated with chronic renal failure and long-term dialysis, such as dialysis-related amyloidosis and atherosclerosis. METHODS: We established a highly sensitive and specific competitive enzyme-linked immunosorbent assay (ELISA) for plasma pentosidine and applied it to large numbers of plasma samples including haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients. We compared their plasma pentosidine levels determined by the competitive ELISA with those determined by high-performance liquid chromatographic (HPLC) assay currently used. RESULTS: The plasma pentosidine levels determined by the ELISA were correlated well with those determined by sophisticated instrumental HPLC assay, both in non-diabetic and diabetic dialysis patients. Both analyses yielded comparable results, with over 8-fold higher plasma pentosidine levels in HD and CAPD patients, irrespective of the presence or absence of diabetes, as compared to normal subjects and non-uraemic diabetic patients. CONCLUSIONS: The competitive ELISA will provide a rapid and convenient determination of plasma pentosidine content and thus be useful to assess the carbonyl stress in uraemic patients.

Advanced glycation and lipidoxidation of the peritoneal membrane: respective roles of serum and peritoneal fluid reactive carbonyl compounds.

BACKGROUND: Advanced glycation of proteins has been incriminated in the progressive alteration of the peritoneal membrane during chronic peritoneal dialysis (PD). Advanced glycation end products (AGEs) result from a modification of proteins by reactive carbonyl compounds (RCOs). RCOs resulting from glucose breakdown are present in commercial PD fluid. They also accumulate in uremic plasma. The present study was undertaken to evaluate the respective contribution of these two sources of RCOs in the genesis of peritoneal AGEs. METHODS: Three major RCOs formed during heat sterilization of PD fluid, that is, glyoxal, methylglyoxal, and 3-deoxyglucosone, and total RCOs were measured in commercial PD fluid and in PD effluent. The generation of pentosidine, used as a surrogate marker for AGEs, during one-week incubations of PD fluid and effluent samples fortified with bovine serum albumin (BSA) was measured by high-performance liquid chromatography. Peritoneal samples were stained with antibodies specific for two AGEs derived from carbohydrate-dependent RCOs, Nepsilon-(carboxymethyl)lysine (CML) and pentosidine, or for two advanced lipoxidation end products (ALEs) derived from lipid-dependent RCOs, malondialdehyde (MDA)-lysine and 4-hydroxynonenal (HNE)-protein adduct. RESULTS: Glyoxal, methylglyoxal, and 3-deoxyglucosone were identified in commercial PD fluid. Their levels in PD effluents decreased with dwell time probably by diffusion into blood circulation. In contrast, the levels of total RCOs were initially low in commercial PD fluid, increased in PD effluent with dwell time probably by diffusion from circulation into the peritoneal cavity, and after 12 hours, reached values observed in uremic serum. The relevance of the rise in total RCOs for AGE formation is demonstrated by a parallel increase in the generation of pentosidine during incubations of PD effluents. In contrast with RCOs present in glucose-rich PD fluid, RCOs diffusing from uremic circulation originate from both carbohydrates and lipids. Their role in the modification of peritoneal proteins is demonstrated by the immunohistochemical study of peritoneal tissue. Two AGEs and two ALEs increase in parallel in the mesothelial layers and in vascular wall of small arteries in the peritoneum. CONCLUSIONS: Protein modification of the peritoneum is determined not only by RCOs originating in PD fluid, but also by RCOs originating from the uremic circulation. The present data might be relevant to current attempts to improve PD fluid toxicity by lowering its glucose content.

Accumulation of carbonyls accelerates the formation of pentosidine, an advanced glycation end product: carbonyl stress in uremia.

Advanced glycation end product (AGE) formation is related to hyperglycemia in diabetes but not in uremia, because plasma AGE levels do not differ between diabetic and nondiabetic hemodialysis patients. The mechanism of this phenomenon remains elusive. Previously, it was suggested that elevation of AGE levels in uremia might result from the accumulation of unknown AGE precursors. The present study evaluates the in vitro generation of pentosidine, a well identified AGE structure. Plasma samples from healthy subjects and nondiabetic hemodialysis patients were incubated under air for several weeks. Pentosidine levels were determined at intervals by HPLC assay. Pentosidine rose to a much larger extent in uremic than in control plasma. Pentosidine yield, i.e., the change in pentosidine level between 0 and 4 wk divided by 28 d, averaged 0.172 nmol/ml per d in uremic versus 0.072 nmol/ml per d in control plasma (P < 0.01). The difference in pentosidine yield between uremic and control plasma was maintained in samples ultrafiltrated through a filter with a 5000-Da cutoff value and fortified with human serum albumin (0.099 versus 0.064 nmol/ml per d; P < 0.05). Pentosidine yield was higher in pre- than in postdialysis plasma samples (0.223 versus 0.153 nmol/ml per d; P < 0.05). These results suggest that a large fraction of the pentosidine precursors accumulated in uremic plasma have a lower than 5000 Da molecular weight. Addition of aminoguanidine and OPB-9195, which inhibit the Maillard reaction, lowered pentosidine yield in both uremic and control plasma. When ultrafiltrated plasma was exposed to 2,4-dinitrophenylhydrazine, the yield of hydrazones, formed by interaction with carbonyl groups, was markedly higher in uremic than in control plasma. These observations strongly suggest that the pentosidine precursors accumulated in uremic plasma are carbonyl compounds. These precursors are unrelated to glucose or ascorbic acid, whose concentration is either normal or lowered in uremic plasma. They are also unrelated to 3-deoxyglucosone, a glucose-derived dicarbonyl compound whose level is raised in uremic plasma: Its addition to normal plasma fails to increase pentosidine yield. This study reports an elevated level of reactive carbonyl compounds ("carbonyl stress") in uremic plasma. Most have a lower than 5000 Da molecular weight and are thus partly removed by hemodialysis. Their effect on pentosidine generation can be inhibited by aminoguanidine or OPB-9195. Carbonyl stress might contribute to AGE modification of proteins and thus to clinically relevant complications of uremia.

Effect of dwell time on carbonyl stress using icodextrin and amino acid peritoneal dialysis fluids.

BACKGROUND: Deterioration of the peritoneal membrane limits the technical survival of peritoneal dialysis (PD). Advanced glycation of the membrane has been incriminated in this evolution. Advanced glycation end products (AGEs) develop under the influence of glucose and of its degradation products, mainly reactive carbonyl compounds (RCOs) such as glyoxal (GO), methylglyoxal (MGO), and 3-deoxyglucosone (3-DG). The present study was undertaken to evaluate the impact of recently developed glucose-free PD fluids on AGE generation. METHODS: Recently developed glucose-free PD fluids containing either icodextrin or amino acids were investigated. GO, MGO, and 3-DG [high-performance liquid chromatography (HPLC)] and total RCOs (spectrophotometry) were measured in fresh solutions and in effluents after various dwell duration. The AGE formation potential of PD fluids and effluents was assessed by incubation at 37 degrees C, for one week, with bovine serum albumin and by the eventual measurement of pentosidine (HPLC) and Nepsilon-carboxymethyllysine (CML; gas chromatography/mass spectrometry). RESULTS: GO, MGO, and 3-DG (P < 0. 001) as well as total RCOs levels (P < 0.01) were significantly lower in icodextrin and amino acid PD fluid than in commercial, heat-sterilized, 1.36% glucose PD fluid. Pentosidine and CML generation were also significantly lower (P < 0.001) in icodextrin and amino acid PD fluid than in conventional 1.36% glucose PD fluid. The levels of total RCOs, however, increased in icodextrin and amino acid PD fluid effluents with dwell time. AGE formation potential rose accordingly, as demonstrated by a parallel increase in the generation of pentosidine and CML during incubation of PD effluents. CONCLUSION: The present data demonstrate lower RCO contents and AGE formation potential in fresh icodextrin and amino acid PD fluids than in fresh heat-sterilized glucose PD fluids. However, this difference decreases progressively during dwell time, mainly as a result of the influx of total RCOs.

Specific tissue distribution of megsin, a novel serpin, in the glomerulus and its up-regulation in IgA nephropathy.

Mesangial cells play critical roles in maintaining a structure and function of the glomerulus. We previously cloned a novel mesangium-predominant gene, megsin, a new serine protease inhibitor. To clarify localization and roles of megsin protein, we raised polyclonal antibodies to megsin. By immunohistochemistry, megsin protein was specifically identified in the mesangial area. The amount of megsin protein was increased in glomeruli of patients with IgA nephropathy than in those of normal individuals and of patients with minimal change nephrotic syndrome or membranous nephropathy, suggesting a pathophysiological role of megsin as a functional modulator of mesangial functions in situ.

Immunohistochemical evidence for an increased oxidative stress and carbonyl modification of proteins in diabetic glomerular lesions.

Advanced glycation end products (AGE) include a variety of protein adducts whose accumulation has been implicated in tissue damage associated with diabetic nephropathy (DN). It was recently demonstrated that among AGE, glycoxidation products, whose formation is closely linked to oxidation, such as carboxymethyllysine (CML) and pentosidine, accumulate in expanded mesangial matrix and nodular lesions in DN, in colocalization with malondialdehyde-lysine (MDA-lysine), a lipoxidation product, whereas pyrraline, another AGE structure whose deposition is rather independent from oxidative stress, was not found within diabetic glomeruli. Because CML, pentosidine, and MDA-lysine are all formed under oxidative stress by carbonyl amine chemistry between protein amino group and carbonyl compounds, their colocalization suggests a local oxidative stress and increased protein carbonyl modification in diabetic glomerular lesions. To address this hypothesis, human renal tissues from patients with DN or IgA nephropathy were examined with specific antibodies to characterize most, if not all, carbonyl modifications of proteins by autoxidation products of carbohydrates, lipids, and amino acids: CML (derived from carbohydrates, lipids, and amino acid), pentosidine (derived from carbohydrates), MDA-lysine (derived from lipids), 4-hydroxynonenal-protein adduct (derived from lipids), and acrolein-protein adduct (derived from lipids and amino acid). All of the protein adducts were identified in expanded mesangial matrix and nodular lesions in DN. In IgA nephropathy, another primary glomerular disease leading to end-stage renal failure, despite positive staining for MDA-lysine and 4-hydroxynonenal-protein adduct in the expanded mesangial area, CML, pentosidine, and acrolein-protein adduct immunoreactivities were only faint in glomeruli. These data suggest a broad derangement in nonenzymatic biochemistry in diabetic glomerular lesions, and implicate an increased local oxidative stress and carbonyl modification of proteins in diabetic glomerular tissue damage ("carbonyl stress").