Seiichiro Hara

Immunohistochemical identification of adrenomedullin in human, rat, and porcine tissue

The histological localization was investigated of adrenomedullin (AM), a novel vasorelaxant peptide originally isolated from human pheochromocytoma. The immunohistological distribution was examined of AM in human, rat, and procine tissues using a polyclonal antibody to a fragment comprising C-terminal amino acids 40–52 of human adrenomedullin [AM(40–52)NH2]. Almost all of the human pheochromocytoma and normal adrenal medullary cells of all three species were immunostained and found to be intensely positive for AM. Furthermore, AM-immunoreactive cells were present in the pancreatic islets, gastrointestinal neuroendocrine system, anterior pituitary, and choroid plexus with some degree of interspecies heterogeneity. These findings indicate that AM-immunoreactive cells are widely distributed in the endocrine and neuroendocrine system, suggesting that AM plays some important role in the control of systemic and local circulation and also of humoral secretion.

Effect of Tonsillectomy Plus Steroid Pulse Therapy on Clinical Remission of IgA Nephropathy: A Controlled Study

BACKGROUND AND OBJECTIVES Few well-designed investigations have examined how tonsillectomy plus steroid pulse therapy affects IgA nephropathy. A prospective, controlled study therefore was performed to compare the effects of combined therapy with those of steroid pulse alone in patients with IgA nephropathy. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Fifty-five patients were followed up for 54.0 +/- 21.2 mo. Thirty-five of them underwent tonsillectomy and steroid pulse therapy (group C), and 20 received steroid pulse monotherapy (group M). Both groups received methylprednisolone intravenously, followed by oral prednisolone (initial dosage 0.5 mg/kg per d) for 12 to 18 mo. Primary evaluation items were a 100% increase in serum creatinine from baseline levels or the disappearance of urinary protein (UP) and/or occult blood (UOB) indicating clinical remission. RESULTS At 24 mo after the initial treatment, the ratios of the UP and UOB disappearance were higher in group C than in group M, and the therapeutic effect persisted until the final observation. None of group C achieved a 100% increase in serum creatinine from the baseline level, whereas one patient in group M developed ESRD during the observation period. The histologic findings of repeated biopsy specimens from 18 patients revealed that mesangial proliferation and IgA deposition were significantly more reduced in group C than in group M. The Cox regression model showed that the combined therapy was approximately six-fold more effective in causing the disappearance of UP than steroid pulse monotherapy. CONCLUSION Tonsillectomy combined with steroid pulse treatment can induce clinical remission in patients with IgA nephropathy.

Novel distribution of adrenomedullin-immunoreactive cells in human tissues

Abstract Adrenomedullin (AM) is a novel hypotensive and vasodilator peptide. We previously examined the localization of AM in human, rat, and porcine tissues using a polyclonal antibody against synthetic human AM[40–52]. We demonstrated that AM is widely distributed in the endocrine and neuroendocrine systems, but not in the heart, kidney, or blood vessels, although high levels of AM mRNA were detected in the latter tissues. In this study, we further investigated the distribution of AM by using two newly developed monoclonal antibodies against synthetic human AM peptides, [12–25] and [46–52]. AM immunoreactivity was observed in cardiac myocytes, vascular smooth muscle cells, endothelial cells, and renal distal and collecting tubules. In addition, AM-immunoreactive (IR) cells were found in mucosal and glandular epithelia of the digestive, respiratory, and reproductive systems, as well as the endocrine and neuroendocrine systems. These findings indicate that AM-IR cells are more widely distributed in human tissues and suggest that AM might play multiple biological roles in humans.

Effect of Sevelamer on Dyslipidemia and Chronic Inflammation in Maintenance Hemodialysis Patients

Background: Hemodialysis (HD) patients often experience cardiovascular events, that might be related to altered calcium–phosphate metabolism, dyslipidemia, and chronic inflammation in addition to hypertension. Sevelamer, a non-calcium-containing phosphate binder, may improve the lipid profile of HD patients. However, the influence of sevelamer on chronic inflammation has not been clarified. Methods: We enrolled 36 maintenance HD patients with a serum calcium (Ca) or phosphate (P) level constantly greater than 9.5 mg/dL and 5.5 mg/dL, respectively. The dose of sevelamer was titrated to achieve a serum Ca and P in the target ranges. The study period was 24 weeks. Patients underwent the following measurements: bone mineral markers, lipids, and a high-sensitivity C-reactive protein (hs-CRP). Results: In the 28 patients who completed the study, sevelamer significantly reduced the mean non-high-density lipoprotein cholesterol (non-HDL-C) level by 15% and 20% (p < 0.0001) after 12 and 24 weeks, respectively, in addition to reducing the serum P level and Ca × P product. Similarly, there was a significant reduction of the serum hs-CRP level after 12 and 24 weeks [median at baseline: 1.03 mg/dL (interquartile range 0.26–3.98 mg/dL) versus 0.57 (0.17–1.47) and 0.38 (0.16–1.03), respectively, p = 0.0259]. The reduction rate of hs-CRP was significantly correlated with those of non-HDL-C (r = 0.451, p < 0.0401) and P (r = 0.453, p < 0.0008) Conclusion: Hs-CRP levels were reduced by sevelamer administration, as well as non-HDL-C, P, and the Ca × P product. Sevelamer may have an anti-inflammatory effect, in addition to lowering phosphate and lipid levels in HD patients.

Renal Biopsy in Elderly Patients: A Clinicopathological Analysis

As the numbers of aging patients with manifestations of renal disease increase, the elderly must frequently undergo renal biopsies. This study examined the characteristics of clinicopathological correlations in elderly patients. Medical and clinical records from renal biopsies registered in two hospitals between January 2000 and December 2004 were reviewed. Among 406 patients (female: male 224/182; age 43.9 ± 18.8 years, mean ± SD) who underwent renal biopsies, 61 (15.1%) who were aged 65 years and older (female: male, 29/32; age 72.8 ± 5.2 years) were selected. The elderly usually underwent percutaneous renal biopsies for renal diseases such as nephrotic syndrome (43%) and acute or rapidly progressive renal failure (A/RPRF, 39%). Focal/segmental glomerulosclerosis (23%), minimal change disease (19%), and membranous nephropathy (15%) are frequently diagnosed based on biopsy specimens from patients with nephrotic syndrome. Among patients presenting with A/RPRF, 17 (71%) and 4 (17%) had pauci-immune, MPO-ANCA positive, crescentic glomerulonephritis and interstitial nephritis, respectively, and benefited from therapeutic intervention. Histopathological and pre-biopsy clinical diagnoses differed in nine (15%) patients. The complication rate after biopsy was low (3%). Primary glomerular diseases presenting with nephrotic syndrome and primary crescentic glomerulonephritis associated with rapidly progressive renal failure were the most frequently diagnosed among the elderly who underwent renal biopsy. Percutaneous renal biopsy provides clinically useful information about the elderly because clinical presentation and the predicted diagnosis sometimes vary.

Multivariate analysis of prognostic factors and effect of treatment in patients with IgA nephropathy.

Background: Although the clinical and histological prognostic factors of IgA nephropathy have been investigated in detail, the value of treatment in terms of renal outcome is not well understood. Methods: The authors examined data from 237 patients with IgA nephropathy (age 31.4 ± 13.5 years, mean ± SD) who had been followed-up for at least six months (follow-up periods, 62.3 ± 45.5 months). The authors initially tested the significance of prognostic factors (age, sex, systolic blood pressure, proteinuria, serum creatinine, and histological severity) and treatment strategies (steroid therapy, renin-angiotensin system inhibitors and tonsillectomy) on renal outcome with univariate analysis, then evaluated the findings using the Cox proportional hazards model. Results: Univariate and multivariate analyses showed that among the prognostic variables, a high level of serum creatinine at renal biopsy, large amounts of proteinuria, and extensive histological injury were significant risk factors for end-stage renal failure. Kaplan-Meier analysis showed that the renal survival rates associated with these factors were significantly poorer depending on their severity. Univariate analysis revealed that tonsillectomy was the only significant treatment that contributes to the maintenance of renal survival. Moreover, urinary abnormalities disappeared at a significantly higher frequency when patients were treated by tonsillectomy. The Cox proportional hazards model showed that steroid therapy independently contributed to improve renal prognosis in addition to tonsillectomy, and the hazard ratios were 0.26 (95% CI, 0.07 to 0.93) and 0.37 (95% CI, 0.14 to 0.99), respectively. Conclusion: Steroid therapy and tonsillectomy can independently improve renal outcome in patients with IgA nephropathy.

Elevated Osteoprotegerin Levels Predict Cardiovascular Events in New Hemodialysis Patients

Background: Patients on hemodialysis (HD) frequently experience cardiovascular events associated with vascular calcification. We investigated the involvement of osteoprotegerin (OPG), an inhibitor of vascular calcification, in the incidence of cardiovascular events and mortality among new HD patients. Methods: We conducted a prospective cohort study of the association of serum OPG levels with morbidity and mortality in subjects who became new HD patients between June 2000 and May 2006. Results: A total of 99 patients (age 58.9 ± 14.6 years, 65 male, 34 female) were prospectively followed up for 41.5 ± 20.2 months. During this period, 27 patients developed cardiovascular events and 12 died of causes related to cardiovascular disease. When divided into 2 groups according to OPG levels, the high OPG group showed a higher prevalence of cardiovascular morbidity and mortality compared with the low OPG group. Cox’s proportional hazards analysis associated the new onset of cardiovascular events with the high OPG group (HR 2.88, 95% CI 1.09–7.62, p = 0.033). Furthermore, the high OPG group at the start of HD was significantly associated with older age, male gender and a high aortic calcification index. Conclusions: Elevated levels of serum OPG in new HD patients may predict subsequent cardiovascular events.

Increased adrenomedullin immunoreactivity and mRNA expression in coronary plaques obtained from patients with unstable angina

Objective: To examine the expression and localisation of adrenomedullin in human coronary atherosclerotic lesions from patients with unstable angina (UAP) and stable angina (SAP), and to study the relation between adrenomedullin expression and plaque instability. Design: A retrospective observational study. Patients: Directional coronary atherectomy samples were obtained from 15 patients with UAP and 12 with SAP. Methods: The localisation of adrenomedullin was examined by immunohistochemistry, and adreno-medullin mRNA expression was measured by quantitative polymerase chain reaction. Results: Adrenomedullin immunoreactivity was preferentially localised in macrophages, intimal smooth muscle cells, and proliferated microvessels. The mean number of adrenomedullin positive cells in five high power fields (× 400) per specimen was higher in patients with UAP than in those with SAP (mean (SEM), 110 (13) v 76 (7); p < 0.05); and the ratio of adrenomedullin positive to total cells was higher in patients with UAP (43.0 (2.2)% v 34.2 (2.0)%; p < 0.01). More adrenomedullin mRNA was expressed in the plaque of patients with UAP than in those with SAP (60.4 (16.9)% v 9.7 (3.3)%; p < 0.01). Conclusions: The findings suggest that adrenomedullin is involved in the development of atherosclerosis and plaque instability in human coronary arteries, in an autocrine or paracrine manner.

Recent Therapeutic Strategies Improve Renal Outcome in Patients with IgA Nephropathy

Background/Aims: Various treatment options for IgA nephropathy (IgAN) have been developed, particularly over the past decade. Nevertheless, whether such therapeutic interventions improve actual renal outcome as compared with previous therapies remains obscure. Methods: We examined data from 304 patients with IgAN whose serum creatinine value at renal biopsy was <2.0 mg/dl and who had been followed up for >12 months. We assigned the patients to groups according to the period of diagnosis (group E, between 1981 and 1995, n = 130; group L, between 1996 and 2006, n = 174). Results: Significantly more patients had received steroid therapy and renin-angiotensin system inhibitors (RAS-I) in group L than in group E (steroid 51.7 vs. 15.4%, p < 0.001; RAS-I 42.0 vs. 1.5%, p < 0.001). Forty patients overall reached end-stage renal disease (ESRD) within 81.9 ± 55.1 months of observation. Kaplan-Meier analysis showed that the 10-year renal survival rate of group L persisted and significantly differed from that of group E (95.7 vs. 75.2%, p = 0.005). The Cox proportional hazards model adjusted for known prognostic markers demonstrated that initial therapeutic interventions in group L prevented ESRD, with a hazard ratio of 0.29 (95% CI 0.11–0.76, p = 0.011). Conclusion: Although this study is not a prospective trial, our results indicate that aggressive therapeutic intervention for IgAN over the past decade has improved actual renal outcome.

Radial Augmentation Index is Related to Cardiovascular Risk in Hemodialysis Patients

Abstract:  Cardiovascular accidents related to atherosclerosis are the leading cause of death among hemodialysis patients, which makes continuous monitoring of their cardiovascular status crucial. Recently, a handy device for monitoring the augmentation index (AIx) in the radial artery was introduced in Japan, enabling the use of the AIx in addition to pulse wave velocity (PWV) in the management of hemodialysis patients. In this study the AIx, PWV, abdominal aortic calcification index (ACI), and left ventricular mass index (LVMI) were serially assessed in 108 hemodialysis patients. The radial AIx was monitored using a newly introduced tonometer (HEM‐9010AI), and the interrelationships among the measured parameters and their contributions to the risk of cardiovascular accidents were evaluated. The radial AIx was significantly higher in hemodialysis patients than in healthy subjects (N = 50) and was well correlated with risk markers such as LVMI (r = 0.30, P = 0.019) and ACI (r = 0.38, P < 0.001), but not with PWV. Multiregression analysis showed that radial AIx was also significantly associated with LVMI, ACI and blood pressure; PWV was associated with other parameters such as age, blood pressure, and ACI. The AIx and ACI were both significantly increased in patients with cardiovascular complications. Although PWV was strongly increased in the hemodialysis patients, it failed to discriminate between these subgroups of high‐risk patients. The radial AIx is closely associated with aortic calcification, cardiac hypertrophy, and a history of cardiovascular accidents in hemodialysis patients, and could be a useful marker for management of these patients.