Akihide Nakao

Association of eNOS Glu298Asp Polymorphism With End-Stage Renal Disease

Abstract—Nitric oxide (NO) derived from endothelial cells is profoundly related to the maintenance of physiological vascular tone. Impairment of endothelial NO generation brought about by gene polymorphism is considered the major deterioration factor for progressive renal disease, including diabetic nephropathy. The present study aimed to elucidate the Glu298Asp polymorphism of endothelial NO synthase (eNOS) in patients with end-stage renal disease (ESRD) and its role as a predisposing factor for cardiovascular complications. Glu298Asp in exon 7 of the eNOS gene was determined by polymerase chain reaction, followed by restriction fragment length polymorphism analysis, in ESRD patients (n=185) and compared with that of unrelated healthy individuals (n=304). The occurrence of 298Asp was significantly higher in the ESRD group (P =0.0020; odds ratio [OR] 1.65; 95% confidential interval [CI]: 1.21 to 2.25). In this group, 72 patients had type 2 diabetes mellitus (DM). Although 298Asp did not reach a significant level in the non-DM ESRD subgroup, the occurrence of 298Asp was significantly higher in DM-derived ESRD patients (P =0.0010; OR 2.02; 95% CI: 1.37 to 3.07). The functional effect of the Glu298Asp was examined using Chinese hamster ovary (CHO) cells stably overexpressing either 1917G or 1917T. NO-selective electrode measurements and fluorometric nitrite assay revealed a statistically significant difference in NO production or nitrite accumulation between CHO 1917G and 1917T (P <0.01). These data indicated that Glu298Asp is the predisposing factor in ESRD, especially DM-derived ESRD. The functional difference in NO generation depending on eNOS with either glutamate or aspartate at position 298 was also confirmed in vitro.

Serum protein acrolein adducts: utility in detecting oxidant stress in hemodialysis patients and reversal using a vitamin E-bonded hemodialyzer

Accumulating evidence indicates that protein modification by acrolein is one of the major hallmarks of atherosclerosis. The purpose of the present study was to evaluate the serum acrolein-modified protein adduct (Acr) level in end-stage renal disease (ESRD), and to elucidate the efficacy of vitamin E-bonded hemodialyzer in reducing Acr in a crossover trial. A significant increase in Acr was found in ESRD patients compared with healthy controls (p <.001). In ESRD, the Acr level of those patients with type 2 diabetes mellitus (DM) was significantly higher compared with the non-DM group (p <.05). Forty-one ESRD patients who exhibited Acr levels higher than the mean value in ESRD were treated by vitamin E-bonded hemodialyzer for 6 months. After 6 months of treatment, Acr levels were decreased to those found in healthy individuals (p <.001). When hemodialyzers were switched back from vitamin E bonded to the original regular ones, Acr levels increased to nearly their initial levels after 3 months (p <.001), compared with the 6 month time point. These results suggest the potential of Acr as an oxidative stress marker in ESRD, and that vitamin E-bonded hemodialyzer treatment is a reasonable approach to reduce oxidative stress in ESRD.

Increased leukotriene A4 hydrolase expression in the heart of angiotensin II‐induced hypertensive rat

Leukotriene A4 (LTA4) hydrolase is essential for the conversion of LTA4 to LTB4, an inflammatory lipid mediator. We investigated whether LTA4 hydrolase was regulated in the heart by angiotensin II (ang II) infusion. Continuous ang II infusion via an osmotic minipump for up to 7 days upregulated mRNA and protein levels of LTA4 hydrolase (∼3.5‐fold of control) in the heart in a pressor‐dependent manner. Immunohistochemistry demonstrated intense LTA4 hydrolase staining in the myofibroblast as well as migrated monocytes/macrophages. These data suggest that the cardiac LTA4 hydrolase‐LTB4 system plays a positive role in the promotion of cardiac inflammation in hypertension.

Double Filtration Plasmapheresis Can Decrease Factor XIII Activity

Abstract:  Factor XIII (FXIII) produces cross‐linkages among fibrin molecules within fibrin clots. Its deficiency is related with bleeding diathesis or retardation of wound healing. We report the possibility that intense double filtration plasmapheresis (DFPP) is associated with decreased FXIII activity. Five patients with various primary diagnoses were treated with DFPP and their FXIII activity was measured. Coagulation test results remained almost normal, but FXIII activities declined to less than 20% of their initial value before starting DFPP and 10% after DFPP in most cases. The cases that received intense DFPP therapy exhibited profoundly decreased FXIII activity. The clinical course demonstrated that DFPP caused the FXIII decrease. Fortunately, with careful observation, none of the patients experienced fatal bleeding. Only one case required fresh frozen plasma and an open hemostatic procedure because of prolonged postoperative bleeding. In general, DFPP most efficiently removes substances with the following characteristics: adequate molecular weight; long half‐life; and small extravascular distribution volume. The FXIII properties meet all these characteristics. Consequently, we should devote much attention to FXIII activity during DFPP because it cannot be estimated from the usual coagulation tests. Patients who receive DFPP therapy, especially intensified therapy, should have FXIII measured during the course of therapy. Results show that DFPP can decrease FXIII activity. For this reason we recommend the measurement of FXIII when patients receive intense DFPP therapy with albumin replacement.

Puromycin aminonucleoside induces apoptosis and increases HNE in cultured glomerular epithelial cells

Abstract Puromycin aminonucleoside induces apoptosis and increases 4-hydroxy-2-nonenal (HNE) in cultured glomerular epithelial cells. We have previously reported the detachment of cultured glomerular epithelial cells (GECs) from their substrata by puromycin aminonucleoside (PAN) treatment. In this study we explored whether or not apoptosis was involved in the mechanisms of the detachment. DNA fragmentation on gel electrophoresis was clearly shown by 10 −3 M PAN treatment of GECs. Nuclear staining by Hoechst 33342 indicated the greatest number of apoptotic cells at 10 −3 M PAN for 48 h treatment. Similarly, TUNEL methods revealed maximal apoptotic cells at 10 −3 M PAN for 48 h treatment. Caspase-3 (like) protease activity increased at 10 −3 M PAN, and decreased at 2 × 10 −3 M PAN for 48 h treatment as well as at 10 −3 M PAN for 60 h treatment. Pretreatment with 2′-deoxycoformycin (DCF), inhibitor of adenosine deaminase, abolished these effects of PAN on cultured GECs. PAN treatment increased HNE, a lipid peroxide adduct, modified protein in cultured GECs, which was also prevented by pretreatment by DCF. These results for the first time indicate that the PAN-induced detachment of GECs from culture substrata is mediated at least in part through apoptosis via oxidative stresses by adenosine deaminase activity.

Haplotype analysis of NAD(P)H oxidase p22 phox polymorphisms in end-stage renal disease

AbstractNAD(P)H oxidase is one of the most important sources of reactive oxygen species and has been demonstrated to be upregulated by angiotensin II in the kidney. Given the effect of angiotensin-converting enzyme inhibitors on the progression of both diabetic and non-diabetic renal disease, we hypothesized that the polymorphisms of NAD(P)H oxidase are associated with development of end-stage renal disease (ESRD). We examined five polymorphisms in the CYBA gene encoding the p22 phox component of NAD(P)H oxidase, including 242C/T and 640A/G polymorphisms in 467 ESRD patients and 490 healthy individuals. The T allele of the 242C/T polymorphism showed a protective effect against ESRD only in the nondiabetic (non-DM) group (P=0.0095), and haplotype estimation revealed that the frequency of 242C-640A was higher in the non-DM group (46.7%) than in the control group (39.7%). The CC-AA genotype was still significantly associated with ESRD without diabetes after adjusting for confounding factors (P=0.035). In contrast, there was no difference between the DM group and the control group. In conclusion, we identified a risk haplotype for nondiabetic ESRD in the CYBA gene using haplotype analysis. Haplotype analysis proved useful for elucidating the genetic contribution of NAD(P)H oxidase p22 phox to ESRD.

Successful Treatment by Double Filtrate Plasmapheresis in a Pregnant Woman With the Rare P Blood Group and a History of Multiple Early Miscarriages

Abstract:  Individuals of P type, a rare blood group, have anti‐PP1Pk antibody in their serum, which causes spontaneous abortion in the early stages. We report a patient of p type suffering from multiple spontaneous abortions. We also review previously reported cases from published work. A 36‐year‐old woman (gravida 2, para 0) was referred to our hospital because of habitual abortion. At the third pregnancy, we started double filtration plasmapheresis (DFPP) from 7 weeks 3 days to remove the antibody. We attained rapid decline in the titer and normal fetal growth. Gradual tapering of the DFPP frequency caused neither a rebound of the titer nor growth retardation. During the course, she experienced only one episode of catheter infection as an adverse effect. At 37 weeks 3 days, after 57 DFPP repetitions, a 2496 g girl was delivered by cesarean section. The infant suffered neither from anemia nor from severe jaundice. A review of previous reports indicates that the titer of the pathogenic antibody should be kept as low as possible from the early gestational stage in P‐incompatible habitual abortion cases, otherwise the case typically comes to an unfavorable outcome. Plasma exchanges with fresh plasma potentially induce contamination by either known or unknown pathogens. Such risks are reduced using DFPP because the volume of albumin solution that replaces fresh plasma is less than that by plasma exchange. The present case, along with previous reports, shows that DFPP is an effective therapy for treating P‐incompatible pregnancy. 

Distribution of β2-adrenergic receptor mRNA expression along the hamster nephron segments

Distribution of β2‐adrenergic receptor mRNA expression along the microdissected hamster nephron segments was examined by the reverse transcription‐polymerase chain reaction (RT‐PCR) technique. Conventional RT‐PCR using a set of primers on separate exons could not be applied for the detection of β2‐adrenergic receptor mRNA because of its intronless nature. We used the ‘rapid amplification of cDNA ends’ protocol [(1985) Proc. Natl. Acad. Sci. USA 85, 8998‐9002] as a maneuver for RT‐PCR of an intronless gene. Using this method, we successfully located hamster β2‐adrenergic receptor mRNA only in glomeruli and early proximal convoluted tubule along the nephron segments tested.

Functional Polymorphism of the Myeloperoxidase Gene in Hypertensive Nephrosclerosis Dialysis Patients

Myeloperoxidase (MPO) may play an important role not only in host defense reactions but also in local inflammations, especially in atherosclerotic diseases such as hypertensive nephrosclerosis (HN). Paradoxically, MPO-deficient mice have been reported to show increased atherosclerosis compared with wild mice, although higher MPO levels are thought to exacerbate atherosclerotic disease. To clarify the genetic role of MPO in HN, we examined the function and distribution of the −463G/A polymorphism located in the promoter region of the MPO gene with ex vivo flow cytometry analysis and a study in end-stage renal disease patients, respectively. This polymorphism has been reported to have a functional significance in vitro, with the A allele being associated with lower MPO expression. In the present study, we also found significantly higher reactive oxygen species (ROS) production with peripheral neutrophils isolated from subjects with the GG genotype compared with those from subjects with other genotypes by flow cytometry assay with 2-[6-(4′-amino) phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (APF), which shows higher sensitivity with hypochlorite (OCl−). Genotyping the −463G/A polymorphism in HN, chronic glomerulonephritis (CGN) and diabetic nephropathy (DM) patients who were under hemodialysis treatment demonstrated that the GG genotype was more frequent in the HN group than in the CGN and DM groups. However, the distribution of the GG genotype in the HN group was similar to that in healthy individuals. Although the −463G/A polymorphism is associated with ROS production, careful interpretation may be required to conclude that the −463G/A polymorphism can serve as a useful marker of atherosclerosis and cardiovascular events in dialysis patients.

Pharmacokinetics of Cetirizine in Chronic Hemodialysis Patients: Multiple-Dose Study

The serum concentration-time profiles of cetirizine were measured in 8 male end-stage renal failure (ESRF) patients on chronic hemodialysis (HD). Cetirizine (5 mg) was ingested three times a week during the predialysis period. Blood samples were drawn for basal level evaluation, before and after dialysis on 3 days per week, and before HD the following week. The serum levels of cetirizine were measured using a validated atmospheric-pressure ionization liquid chromatography-tandem mass spectrometry method. Basal levels of cetirizine in HD patients were confirmed to be 0 ng/ml. The predialysis levels of cetirizine on days 1, 3, 5, and 8 were (mean ± SD) 2.74 ± 7.76, 34.16 ± 21.55, 35.58 ± 13.43, and 22.47 ± 12.92 ng/ml, respectively. The postdialysis levels of cetirizine 4–5 h after ingestion were as follows (ng/ml): day 1, 103.11 ± 37.27; day 3, 131.34 ± 51.18, and day 5, 136.48 ± 48.72. Between dialysis sessions, no supplemental dosage was required to keep the therapeutic range of 14 ng/ml. In addition, the predialysis levels on day 8 were not statistically different from the basal levels. Evidence from the multiple-dose study supports the clinical use of cetirizine for ESRF patients on HD. Thus, it is concluded that a prescription of 5 mg cetirizine three times a week during the predialysis period will be the effective and safety renal dosage for ESRD patients on HD.