Uric acid levels predict future blood pressure and new onset hypertension in the general Japanese population.

We tested the hypothesis that uric acid levels predict new-onset hypertension in the Japanese general population. Normotensive individuals who visited our hospital for a yearly health checkup (n=8157, men=61.0% and age=50.7±12.2 years) were enrolled in the present study. After baseline evaluation, participants were followed up for a median of 48.3 months (range 4.9-101.0 months), with the endpoint being the development of hypertension, defined as systolic blood pressure (BP) > or = 140 mm Hg, diastolic BP > or = 90 mm Hg or the use of antihypertensive medication. The impact of uric acid and other cardiovascular risk factors at baseline on future BP and development of hypertension was assessed. During follow-up, 19.0% of women (n=605) and 29.5% of men (n=1469) participants developed hypertension. Incident hypertension was increased across the quartiles for baseline uric acid levels (P<0.0001), and multivariate Cox proportional hazards analysis revealed a significant and independent association between the uric acid level and the onset of hypertension in both men and women participants (P<0.05). Furthermore, uric acid was independently and positively correlated with future BP (P<0.05). Thus, uric acid is an independent predictor of new-onset hypertension in both women and men.

Factors associated with brachial-ankle pulse wave velocity in the general population.

The present study investigated factors that modify or affect arterial stiffness as assessed by brachial-ankle pulse wave velocity (baPWV) in the general population. Subjects had previously participated in a physical checkup program (n=911), and baPWV and urinary albumin and sodium excretion were also measured. Urine albumin was expressed as the ratio of urine albumin to urine creatinine. Individual salt intake was assessed by estimating 24-h urinary salt excretion and expressed as the ratio of estimated salt intake to body weight. The mean blood pressure and baPWV were 127.1±15.2/77.0±9.5 mm Hg and 15.9±3.3 m s(-1), respectively. Univariate analysis demonstrated that baPWV correlated with various factors including age, blood pressure, electrocardiogram voltage (SV(1)+RV(5)), urine albumin and salt intake. Multivariate regression analysis revealed that electrocardiogram voltage (P<0.001), systolic blood pressure (P<0.0001), urine albumin (P<0.001) and salt intake (P<0.001), independently correlated with baPWV after adjustment for other possible factors. Similar results were obtained for participants not taking any medication. These results suggest that the baPWV value is independently associated with individual salt intake and cardiac and renal damage, and could be a useful procedure for identifying individuals with concealed risk of cardiovascular disease.

Effects of up-titration of candesartan versus candesartan plus amlodipine on kidney function in type 2 diabetic patients with albuminuria.

In the present study, we tested the hypothesis that up-titrating the dose of an angiotensin receptor blocker (ARB) is superior to combined treatment with an ARB and a calcium channel blocker for the same degree of blood pressure (BP) reduction, with respect to urinary albumin excretion in diabetic patients treated with a standard dose of the ARB. Hypertensive patients with type 2 diabetes mellitus and albuminuria (≥30 mg g(-1) creatinine) were enroled in the study, and were either started on or switched to candesartan (8 mg per day) monotherapy. After a 12-week run-in period, baseline evaluations were performed and patients with BP ≥130/80 mm Hg were randomly assigned to receive either candesartan (12 mg per day) or candesartan (8 mg per day) plus amlodipine (2.5 mg per day) for a further 12 weeks. The primary end-point was a reduction in urinary albumin levels. Although there was no significant difference in the BP reduction between the two groups, the reduction in urinary albumin was greater in the up-titrated than the combination therapy group (-40±14% vs -9±38%, respectively; P<0.0001). Thus, up-titration of candesartan more effectively reduces urinary albumin excretion than combined candesartan plus amlodipine in hypertensive patients with diabetes for the same degree of BP reduction.

Coronary artery disease investigated using 99mTc-tetrofosmin myocardial SPECT.

BACKGROUND: Coronary artery disease can be diagnosed from stress and delayed images of myocardial single photon emission computed tomography (SPECT) using technetium-99 m-tetrofosmin (TcTF). However, the negative predictive value of stress SPECT images after a single injection of a low tracer dose remains unknown. Thus, the present study investigates whether normal stress SPECT results predict event-free survival. MATERIALS AND METHODS: We screened 302 consecutive patients who were randomly assigned to two groups for myocardial ischaemia using either stress SPECT with a low dose of TcTF (296 MBq, TcTF group, n = 150) or stress together with rest SPECT using thallium(201) chloride (TlCl, 111 MBq; TlCl group, n = 152) as the tracer. A total of 80 patients with abnormal SPECT findings were excluded and the remaining 222 with normal results (age, 66.5 +/- 0.7 years; TcTF/TlCl, 112/110) were enrolled in the present study and followed up for 401 +/- 9 days, with the endpoint being ischaemic cardiac events. RESULTS: The incidence of cardiac events did not differ between the two groups (0.9% and 0.0% in TcTF and TlCl groups, respectively). The cost and duration of TcTF and TlCl SPECT examinations were about 425 and 603 Euros and 50 and 280 min, respectively. CONCLUSIONS: The negative predictive values of stress SPECT using a low dose of TcTF and of combined stress and rest SPECT using TlCl did not differ and both were clinically acceptable. Thus, stress SPECT using low dose TcTF is useful in screening patients for myocardial ischaemia.

Brain natriuretic peptide detects cardiac abnormalities in mass screening.

BACKGROUND: Plasma brain natriuretic peptide (BNP) is elevated in asymptomatic patients with various cardiac abnormalities. We tested the hypothesis that measuring BNP is useful for detecting asymptomatic patients with cardiac abnormalities who are not identified by conventional health check-up programmes. MATERIALS AND METHODS: From 2001 to 2002, 6189 subjects (women 34.0%; mean age 56.6 years) underwent multiphasic health check-ups in our hospital, of which 4818 without cardiac abnormalities as revealed by the health check-up were enrolled in the present study. Their plasma concentrations of BNP were measured. RESULTS: Plasma concentrations of BNP were higher than the normal reference upper limit of our hospital (21.3 pg mL(-1)) in 925 of the 4818 subjects. Echocardiography was performed in 471 subjects who were randomly selected from the 925 subjects with elevated BNP. Abnormal findings were detected in 174 subjects, comprising valvular heart disease in 83, systolic dysfunction in 10, diastolic dysfunction in 54, left ventricular hypertrophy in 41, left ventricular enlargement in 11, left atrial enlargement in 13 and paroxysmal atrial fibrillation in 3. CONCLUSIONS: Since BNP measurement identifies additional subjects with cardiac abnormalities, it is useful for detecting asymptomatic cardiac abnormalities among apparently healthy subjects, and is suitable for use in high-quality mass screening.

Effects of the Cdx-2 polymorphism of the vitamin D receptor gene and lifestyle factors on bone mineral density in a representative sample of Japanese women: the Japanese Population-based Osteoporosis (JPOS) Study.

Using a large-scale representative sample of the Japanese female population, we examined the effects of a single nucleotide polymorphism within a binding site of Cdx-2 in the promoter region of the vitamin D receptor gene on bone mineral density (BMD), and the interactions between this polymorphism and lifestyle factors on BMD. Fifty women were randomly selected from each of the 5-year age-stratified populations (15-79 years) in each of three chosen municipalities as a part of the Japanese Population-based Osteoporosis Study. BMD at the lumbar spine, hip, and distal forearm was measured using dual-energy X-ray absorptiometry at baseline and again in a follow-up study conducted 3 years later. Information on lifestyle factors was collected in a questionnaire and followed up in interviews. The G-to-A polymorphism within the Cdx-2 binding site was determined by a TaqMan allelic discrimination assay. At baseline, 1,340 women were analyzed. The baseline BMD in the ultradistal forearm in premenopausal women with the GG genotype was significantly lower than in those with other genotypes. There was no association between the Cdx-2 genotype and the change in BMD at any of the skeletal sites. We found significant associations between daily milk consumption and baseline BMD at some skeletal sites but only in subjects with the GG genotype. In conclusion, the Cdx-2 polymorphism alone did not have a substantial effect on BMD in Japanese women. However, this polymorphism might have some effect in women with low calcium intake.

Relationship between immunological rejection and matrix GLA protein in cryopreserved vascular allografts.

INTRODUCTION: Cryopreserved tissue allografts used for cardiovascular diseases become calcified as a late complication after transplantation, probably caused by immunological rejection. Recent attention has been focused on the inhibitory effect of matrix Gla protein (MGP) on ectopic vascular calcification, but the behavior of MGP in cryopreserved allografts is uncertain. In this study we examined the relationship between immunological rejection and MGP in cryopreserved rat aortic grafts after transplantation. METHODS: Cryopreserved rat aortae were isografted or allografted intraperitoneally. Fresh isografts were also tested. The grafts were retrieved 9 days after transplantation and the intragraft MGP mRNA was measured by a real-time quantitative PCR method. The effect of daily administration of FK506 on MGP mRNA levels in cryopreserved isografts and allografts after transplantation was also evaluated. RESULTS: There was no significant difference in intragraft MGP mRNA levels between fresh and cryopreserved isografts 9 days after transplantation. MGP expression levels in cryopreserved allografts were significantly lower as compared to those in cryopreserved isografts (P < .01). Daily administration of FK506 enhanced intragraft MGP mRNA (ninefold) in cryopreserved allografts (P < .01), but not in cryopreserved isografts. CONCLUSIONS: Immunological rejection is likely to inhibit MGP expression in cryopreserved vascular allografts, resulting in late-onset calcification.

Brain natriuretic peptide in the prediction of recurrence of angina pectoris.

BACKGROUND: Circulating levels of brain natriuretic peptide (BNP) provide prognostic information for patients with heart failure, but little is known about its prognostic usefulness in patients with stable angina pectoris. We investigated whether BNP could be used as a marker for the prediction of anginal recurrence after successful treatment. DESIGN: Brain natriuretic peptide levels of 77 patients with stable angina pectoris were measured at enrolment and after confirmation of successful treatment (i.e. no anginal attack for at least 6 months: chronic phase) with percutaneous transluminal coronary angioplasty and/or conventional medication. Then, we prospectively followed them up for 25.9 +/- 1.4 months, with the endpoint being a recurrence of anginal attacks. RESULTS: An anginal attack recurred in seven patients. In patients without recurrence, BNP levels in the chronic phase (21 +/- 12 [median +/- median absolute deviation] pg mL-1) were lower than those measured at enrolment (46 +/- 25 pg mL-1, P < 0.0001), whereas the levels in patients with recurrence increased during the same period (from 36 +/- 16 to 72 +/- 42 pg mL-1, P < 0.05). A univariate analysis revealed that the BNP level measured in the chronic phase was the significant predictor of future anginal recurrence. Analysis of the receiver operating characteristic curve indicated that the cutoff level of BNP in the chronic phase was 68 pg mL-1. The Kaplan-Meier method revealed that the incidence of anginal recurrence was higher in patients with higher (71.4%) than lower levels of BNP (2.9%; P < 0.0001). CONCLUSIONS: Measurement of BNP levels after successful therapy is clinically useful for the prediction of recurrence of anginal attacks in patients with angina pectoris.

Circulating concentrations of cardiac proteins indicate the severity of congestive heart failure.

OBJECTIVE: To test the hypothesis that myocardium specific proteins may be useful markers for evaluating the severity of congestive heart failure. METHODS: Serum concentrations of myosin light chain I (MLC-I), heart fatty acid binding protein (H-FABP), creatine kinase isoenzyme MB (CK-MB), and troponin T (TnT) and plasma concentrations of brain natriuretic peptide (BNP) were determined in 48 patients with acute deterioration of congestive heart failure, both before and after effective treatment. RESULTS: Before treatment, MLC-I (mean (SEM) 3.2 (2.2) microg/l), H-FABP (9.0 (3.5) microg/l), TnT (30 (21) ng/l), and BNP (761 (303) ng/l) were higher than the normal reference range, and concentrations of CK-MB (5.4 (2.9) microg/l) were near normal. Treatment of congestive heart failure with conventional medication significantly decreased the concentrations of MLC-I (1.2 (0.3) microg/l, p < 0.0001), H-FABP (6.0 (2.0) microg/l, p < 0.0001), CK-MB (2.9 (1.5) microg/l, p < 0.0001), TnT (9 (1) ng/l, p < 0.001), and BNP (156 (118) ng/l, p < 0.0001). The decreases in H-FABP and CK-MB concentrations after treatment correlated with the decrease in BNP concentrations (p < 0.05). The absolute concentrations of MLC-I, H-FABP, CK-MB, and TnT correlated positively with those of BNP (p < 0.01). CONCLUSIONS: These findings suggest that MLC-I, H-FABP, CK-MB, and TnT may be used as reliable markers for the evaluation of the severity of congestive heart failure.

Human peripheral blood polymorphonuclear leukocytes at the ovulatory period are in an activated state.

The ovulatory process has been compared with inflammation. We investigated the state of female peripheral polymorphonuclear leukocytes (PMN) during menstrual cycles, and found that PMN contained high levels of superoxide, hydrogen peroxide and nitric oxide (NO) during at the peri-ovulatory period. Assuming the cause of this elevation to be a luteinizing hormone (LH), the surge of which preceded the ovulation, we examined the responsiveness of PMN to pituitary LH. The results revealed that this hormone elevated dose-dependently the production of reactive oxygen intermediates (ROI). Furthermore, we demonstrated the mRNA expression of LH receptors and their presence on PMN. The data indicated that the LH surge before on the ovulatory day resulted in general activation of PMN, suggesting that this state of PMN may be a necessary step for initiation of ovulation, rather than a defensive role against infection.

Greater trunk muscle torque reduces postmenopausal bone loss at the spine independently of age, body size, and vitamin D receptor genotype in Japanese women.

Bone mineral density (BMD) is affected by muscle strength. Recently, vitamin D receptor (VDR) genotype was reported to affect muscle strength as well as BMD in Caucasian women. The aim of this study was to evaluate independent effects of muscle strength of the trunk on BMD at the spine and its change over time in Japanese women. We followed 119 healthy postmenopausal women for 4 years and determined the change in BMD at the spine by dual energy X-ray absorptiometry. Isometric peak torque and isokinetic concentric and eccentric peak torque of the trunk flexors and extensors were measured. The VDR genotype was determined by the PCR-RFLP method based on Apa I and Taq I endonuclease digestions defining the absence/existence of the restriction sites as A/a and T/t, respectively. The subjects were 60.1 +/- 6.6 years old, had 0.808 +/- 0.159 g/cm2 of BMD at baseline. The mean annual change in BMD (delta BMD) was -5.6 +/- 10.4 mg/cm2 during the follow-up period. The VDR genotype, defined by Taq I enzyme, significantly related to BMD at baseline and delta BMD showing that the subjects with genotype TT had the lowest BMD at baseline and lost bone most rapidly. However, its effect on muscle strength was not significant. All the trunk muscle strength indices showed significant positive effects on delta BMD, that is, the effects in increasing the gain and reducing the loss of BMD, after controlling for the effects of age, body size and the VDR genotype. The eccentric trunk extensor torque had a significant positive effect on delta BMD in a dose-dependent manner. The effect of this torque was the greatest among all the muscle indices. The net effect of the trunk extensor torque on delta BMD was greater than that of the VDR genotype. The trunk muscle strength was suggested to affect BMD change independently of age, body size, and the VDR genotype. Exercise programs to increase the strength of the trunk muscles would be beneficial for the prevention of osteoporosis regardless of the VDR genotypes.

Association of transforming growth factor-beta1 T29C polymorphism with the progression of diabetic nephropathy.

Diabetes mellitus is a leading cause of end-stage renal disease in the Western world. Histologically, mesangial expansion with increased extracellular matrix protein is observed in patients with diabetic nephropathy. Because transforming growth factor (TGF)-beta promotes extracellular matrix production in response to high glucose, TGF-beta is considered to play a central role in the pathogenesis of diabetic nephropathy. We investigated the association of TGF-beta1 T29C polymorphism and the progression of diabetic nephropathy. Forty patients with type 2 diabetes mellitus were enrolled. All patients had had diabetes for more than 10 years. DNA was extracted from peripheral blood cells, and genotype was determined using real-time polymerase chain reaction method. Patients were classified into three groups according to genotype: TT, TC, and CC. Grade of diabetic nephropathy was determined using the amount of urinary excretion of albumin. Demographic characteristics of the patients with each genotype were not statistically different. No differences in the glycemic control and the mode of therapy were observed. Among patients with three genotypes, the severity of diabetic nephropathy was not statistically different. The patients with TT genotype tended to have a higher rate of progression of nephropathy; however, no statistically significant difference was observed among the three groups. Our results suggest that TGF-beta1 T29C polymorphism is not associated with the progression of diabetic nephropathy. Further studies are required to determine the exact role of this polymorphism in the progression of diabetic nephropathy.

Intragraft expression of p38 and activated p38 MAPK (mitogen-activated protein kinase) in rat small bowel transplantation.

Recent studies suggest that cytotoxic T-lymphocytes expressing p38 mitogen-activated protein kinase (p38MAP kinase) contribute to allograft rejection in clinical heart transplantation. Interleukin-2 (IL-2), a potent T cell mitogen, activates the p38MAP kinase pathway, resulting in phosphorylation of target transcription factors. In this study we investigated the expression of activated p38MAP kinase in intragraft cell infiltrates following rat heterotopic small bowel transplantation and examined the effects of the immunosuppressant FK506 on intragraft expression of activated p38MAP kinase and allograft rejection. Allografts receiving FK506 (0.5 mg/kg per day i. m.) for 7 days as primary anti-rejection therapy had a significant reduction in histopathological evidence of allograft rejection on Day 7, compared to allograft controls. In addition, Western blotting analysis of intragraft cell infiltrates showed a reduction in the expression of activated p38MAP kinase in allografts treated with FK506. We conclude that intragraft cell infiltrate expression of activated p38MAP kinase is an important marker of acute rejection in this animal model of small bowel transplantation, and that FK506 is an effective immunosuppressant, in this situation, that may act in part by preventing the activation of p38MAP kinase.

Role of Ca2+-sensitive protein kinase C in phenylephrine enhancement of Ca2+ sensitivity in rat tail artery.

We investigated the role of protein kinase C (PKC) isoforms on changes in sensitivity of contractile mechanisms to intracellular Ca(2+) (force /[Ca(2+)]i) by phenylephrine (0.1-100 microM) in rat tail arterial helical strips using simultaneous measurements of force and [Ca(2+)]i. Force/[Ca(2+)]Ii induced by phenylephrine was greater than that induced by 80 mM K+. Force/[Ca(2+)]i induced by phenylephrine in physiologic saline solution or low Ca(2+) solution was dependent on the agonist concentration. Removal of Ca(2+) completely abolished the phenylephrine-induced contraction. The PKC inhibitors staurosporine and calphostin C inhibited the increase in force/[Ca(2+)]i induced by phenylephrine to a much greater extent than that induced by 80 mM K+. LY379196, a specific PKCbeta inhibitor, did not inhibit the increase of calcium sensitivity due to phenylephrine. The classic PKC isoforms, alpha, betaI, and II not gamma were demonstrated in the artery by immunohistochemistry. These results suggest that in rat tail arterial smooth muscle, PKCalpha, and not beta or gamma, mediates the increase of changes in sensitivity of contractile mechanisms to intracellular Ca(2+) to high dose of alpha1 receptor stimulation (phenylephrine 100 microM) on nonphysiologic conditions.

Recombinant human bone morphogenetic protein-2 potentiates the in vivo osteogenic ability of marrow/hydroxyapatite composites.

A composite of marrow mesenchymal stem cells (MSCs) and porous hydroxyapatite (HA) has bone-forming capability. To promote the capability, we added recombinant human bone morphogenetic protein-2 (BMP) to the composite. The bone formation was assessed by rat subcutaneous implantation of 4 different kinds of implants, i.e., HA alone, BMP/HA composites, MSCs/HA composites, and the composites containing BMP (MSCs/BMP/HA). Both HA and the BMP/HA composites did not show bone formation at any time after implantation. The MSCs/HA composites showed moderate bone formation at 4 weeks and extensive bone formation at 8 weeks. The MSCs/BMP/HA composites showed obvious bone formation together with active osteoblasts at 2 weeks and more bone formation at 4 and 8 weeks. The MSCs/BMP/HA composites demonstrated high alkaline phosphatase and osteocalcin expression at both the protein and gene levels. These results indicate that the combination of MSCs, porous HA, and BMP synergistically enhances osteogenic potential and provides a rational basis for their clinical application in bone reconstruction surgery.

Magnesium removal impairs the regulatory role of rat endothelium.

Vascular endothelium has been shown to play an important role in the regulation of vascular tone and, hence, impairment of the endothelium may induce hypertension. Although magnesium (Mg) deficiency could induce hypertension, the role of Mg on the endothelium is unclear. We examined the effects of Mg removal on endothelium-dependent and -independent responses using ring preparations of femoral arteries obtained from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Norepinephrine (10(-9)-10(-4) M) evoked concentration-dependent contractions in arteries with endothelium. The maximal response was greater in SHR than in WKY. Removal of external Mg augmented the contraction in WKY but not in SHR. As a result, the contraction obtained in arteries with endothelium was identical in the two groups. Removal of the endothelium enhanced the contraction in both strains, with a greater response occurring in WKY than in SHR in Krebs, but not in Mg-free, solution. As a result, in arteries without endothelium, the contractions were identical in WKY and SHR both in Krebs and Mg-free solutions. Acetylcholine (10(-9)-10(-4) M) evoked concentration-dependent relaxation in arteries with, but not in those without, endothelium obtained from WKY and SHR. The relaxation did not differ between the two strains, nor was it altered by Mg removal. Thus, Mg removal impairs inhibitory function of the endothelium against contraction induced by norepinephrine, without affecting endothelium-dependent relaxation in response to acetylcholine, in the rat femoral artery. The effect of Mg removal is not apparent in SHR. The fact that after removal of external Mg the contraction in response to norepinephrine in arteries with endothelium is identical in WKY and SHR suggests that a normotensive artery with Mg deficiency may mimic a hypertensive artery through endothelial impairment.

In vivo gene gun-mediated transduction into rat heart with Epstein-Barr virus-based episomal vectors.

BACKGROUND: Gene guns have been used to transfer genes into various organs, but there has been no report of successful gene gun-mediated gene transfer into the heart. In this study, we assessed the possibility of gene therapy using a gene gun and an episomal plasmid vector. METHODS: Gene transfer was performed using two sizes of gold particles and two plasmids (an episomal vector and a conventional plasmid vector). From the first to eighth week after the bombardment, rats were sacrificed. The excised hearts were subjected to X-gal staining and histologic examination. To ensure that plasmid was not distributed to organs other than the heart, the presence of the beta-gal sequence was examined by polymerase chain reaction analyses. RESULTS: Gene expression persisted for 6 weeks. The episomal vector apparently contributed to long-lasting expression. Infiltration of monocytes or leukocytes was very faint. The beta-gal DNA was detected in bombarded hearts but not other organs. CONCLUSIONS: Gene gun-mediated transfer of the episomal vector into beating heart may provide a simple, efficient, and useful strategy for gene therapy.