Yukio Maruyama

Effects of long-term pressure overload on regional myocardial glucose and free fatty acid uptake in rats. A quantitative autoradiographic study.

To investigate the effects of long-term pressure overload on regional myocardial substrate use, we performed quantitative autoradiography using 2-deoxy-D-[U-14C]glucose (14C-DG) and beta-methyl[1-14C]heptadecanoic acid (14C-BMHDA) in conscious rats with a 10-week ascending aortic constriction. Heart weight/body weight ratio increased by 27% in aortic-constricted rats as compared with sham-operated rats (p less than 0.01). Myocardial 14C-DG uptake increased (258 +/- 63 vs. 144 +/- 41 nCi/g, p less than 0.01, n = 6 for each group); however, 14C-BMHDA extraction decreased (251 +/- 69 vs. 342 +/- 75 nCi/g, p less than 0.05, n = 7 for each group) in aortic-constricted rats as compared with sham-operated rats. In sham-operated rats, both 14C-DG and 14C-BMHDA uptakes were higher in the left ventricular anterior and lateral walls as compared with the posterior wall or the interventricular septum. In aortic-constricted rats, 14C-DG uptake also increased in the interventricular septum, as well as in the left ventricular anterior and lateral walls, as compared with the posterior wall. There was, however, no regional difference in 14C-BMHDA extraction among these four regions. Myocardial blood flow distribution determined by 4-[N-methyl-14C]iodoantipyrine or myocyte width showed no regional variations among the four regions, either in aortic-constricted or sham-operated rats. Regional interstitial fibrosis was small in either group. The present study suggests that myocardial substrate uptake is altered nonhomogeneously, and that the nonhomogeneity is not because of regional variations in blood flow distribution, myocyte hypertrophy, or interstitial fibrosis. The results of angiotensin II-induced acute pressure overloading in other sham-operated rats, in which a remarkable increase in myocardial 14C-BMHDA extraction (n = 3, p less than 0.01) and no difference in 14C-DG uptake (n = 3) as compared with normotensive sham-operated rats were elicited, suggest that the findings in aortic-constricted rats are not direct responses to increased left ventricular pressure itself but rather should be explained by still unknown factors related to prolonged pressure overload.

Low-Grade Endotoxemia Contributes to Chronic Inflammation in Hemodialysis Patients: Examination With a Novel Lipopolysaccharide Detection Method

Chronic inflammation has recently been proposed to play a major role in the development of cardiovascular disease and mortality among advanced chronic kidney disease (CKD) patients; however, why advanced CKD promotes chronic inflammation is still unclear. We hypothesized that a very low level of plasma endotoxin (lipopolysaccharide [LPS]) contributes to chronic inflammation in advanced CKD patients. We measured the plasma LPS levels using a novel LPS detection method (ESP method, a method for endotoxin detection using laser scattering photometry) concurrently with serum C‐reactive protein (CRP) levels and various blood tests in 17 stable hemodialysis (HD) patients. As a result, the median LPS levels measured by the ESP method was 0.23u2003pg/mL (range, 0.01–3.89) (inflow, start of HD), 0.22u2003pg/mL (<0.01–9.97) (outflow, start of HD), 0.37u2003pg/mL (<0.01–7.42) (inflow, end of HD), and 1.07u2003pg/mL (<0.01–10.66) (dialysate), respectively; statistically significant differences were not detected between them. The predialysis median CRP level was 0.19u2003mg/dL (0.04–3.02). The logarithm of plasma LPS independently correlated with serum CRP (Ru2003=u20030.595, Pu2003=u20030.0103). In multiple (forward stepwise) regression analysis, in which CRP was determined to be the criterion variable, LPS (log), albumin, and the white blood cell count were adopted as independent explanatory variables (Ru2003=u20030.401, −0.397 and 0.387, respectively). In conclusion, the present study revealed a significant relationship between LPS and CRP using the novel ESP method, and suggested that very low‐grade endotoxemia is contributing to systemic inflammation in HD patients.

Influences of pressure surrounding the heart and intracardiac pressure on the diastolic coronary pressure-flow relation in excised canine heart.

We investigated the change in the instantaneous diastolic left coronary pressure-flow relation (DPFR) when the pressure surrounding the heart (SHP), right heart pressure (RHP), and left heart pressure (LHP) were systematically varied. Eight excised and maximally vasodilated canine hearts placed in an air-tight chamber were used. To obtain a capacitance-free DPFR, coronary perfusion pressure was slowly decreased (about 2 mm Hg/sec) during a prolonged diastole. The zero-flow pressure (Pf = 0) and the slope of the DPFR were analyzed. The mean values of the slope did not change significantly throughout the interventions. The mean value of Pf=0 in the control state (SHP = RHP = LHP = 0 mm Hg) was 6.0 ± 2.0 mm Hg (mean ± SD, n = 8), significantly higher than the venous outflow pressure, RHP (p<0.001), and the other two pressures (p<0.001). When SHP was raised to 15 and 30 mm Hg, while the other pressures remained at 0 mm Hg, the mean values of Pf=0 increased to 20.9 ± 2.4 and 35.6 ± 3.1 mm Hg (p<0.001 and p<0.0005, respectively, vs. control). The mean values of Pf =0 when only RHP was elevated to 15 and 30 mm Hg were 16.0 ± 1.5 and 29.3 ± 1.5 mm Hg (p<0.001 and p<0.0005 vs. control). On elevation of LHP to 15 and 30 mm Hg, the mean values of Pf = 0 were 12.0 ± 2.8 and 17.3 ± 3.6 mm Hg (p<0.01 and p<0.01 vs. control). When both SHP and LHP were almost evenly elevated to about 15 and 30 mm Hg, the mean values of Pf = 0 were raised to 22.0 ± 2.9 and 35.3 ± 3.2 mm Hg, respectively. These mean values were not significantly different from those when only SHP was elevated to the comparable levels. The observation that Pf = 0 exceeded RHP in the control state and that RHP, which was elevated above the preceding Pf=0, was identical with the present Pf=0 supports the vascular waterfall mechanism when RHP is low. Furthermore, the evidence that the degree of DPFR shift was almost linearly dependent on the SHP level rather than on the LHP level indicates that the pressure on the epicardial side is one of the factors that determines the pressure at the top of the vascular waterfall.

Human Gene and Protein Database (HGPD): a novel database presenting a large quantity of experiment-based results in human proteomics

Completion of human genome sequencing has greatly accelerated functional genomic research. Full-length cDNA clones are essential experimental tools for functional analysis of human genes. In one of the projects of the New Energy and Industrial Technology Development Organization (NEDO) in Japan, the full-length human cDNA sequencing project (FLJ project), nucleotide sequences of approximately 30 000 human cDNA clones have been analyzed. The Gateway system is a versatile framework to construct a variety of expression clones for various experiments. We have constructed 33 275 human Gateway entry clones from full-length cDNAs, representing to our knowledge the largest collection in the world. Utilizing these clones with a highly efficient cell-free protein synthesis system based on wheat germ extract, we have systematically and comprehensively produced and analyzed human proteins in vitro. Sequence information for both amino acids and nucleotides of open reading frames of cDNAs cloned into Gateway entry clones and in vitro expression data using those clones can be retrieved from the Human Gene and Protein Database (HGPD, http://www.HGPD.jp). HGPD is a unique database that stores the information of a set of human Gateway entry clones and protein expression data and helps the user to search the Gateway entry clones.

Differences in myocardial fluoro-18 2-deoxyglucose uptake in young versus older patients with hypertrophic cardiomyopathy

The purpose of this study was to determine whether regional myocardial glucose use in patients diagnosed as having hypertrophic cardiomyopathy (HC) at a younger age differs from that in those diagnosed at middle to old age. Sixteen patients with HC (group 1 aged less than 40 years (n = 8); group 2 aged greater than 40 (n = 8) were studied using positron emission tomography and fluoro-18 2-deoxyglucose (FDG). All patients were diagnosed as having HC within 6 years of the study. Contiguous regions of interest were selected circumferentially on each cross-sectional image of the left ventricular wall. In each region of interest, % FDG fractional uptake was calculated. In each patient, % left ventricular FDG fractional uptake was determined as a mean value of % FDG fractional uptake in each region of interest. Moreover, as a measure of nonhomogeneity, the % interregional coefficient of variation in FDG fractional uptake was calculated in each patient. Whereas % left ventricular FDG fractional uptake did not differ between the 2 groups, the % interregional coefficient of variation in FDG fractional uptake was increased in group 1 compared with that in group 2 (11.5 +/- 3.6 vs 7.4 +/- 1.6%; p less than 0.02). Interventricular septum/left ventricular posterior wall thickness ratio and total counts in cross-sectional image did not differ between the 2 groups. These data suggest that patients diagnosed as having HC at a younger age have more nonhomogeneous myocardial metabolic characteristics than do patients diagnosed at middle or old age, and support the notion that HC in the young may be different from that in the middle-aged or elderly.

Mechanical interaction between the ventricles

SummaryWe investigated ventricular interaction by the use of six excised, perfused, canine hearts. In this preparation, we could change the filling pressure of the right and left ventricles independently, thereby breaking the normal series-pump arrangement. We found that mechanical ventricular interaction exists in diastole and in systole. Namely, not only decreased diastolic ventricular compliance, but also the reduced performance in either ventricle was found, when the opposite ventricular pressure was increased. Thus, when the opposite ventricular filling pressure increases, we suspect that systolic ventricular function of either ventricle will be depressed significantly by these two factors; i.e., the Frank-Starling effect due to decreased ventricular diastolic volume following decreased diastolic ventricular compliance, and the depressed systolic ventricular function. Clinically, these findings may be important in considering the mechanism of the occurrence of simultaneous reduced performance of both ventricles in cases when only one side of the ventricle is affected hemodynamically and its filling pressure is greatly increased in various pathological states such as heart failure.

Do serum hepcidin-25 levels correlate with oxidative stress in patients with chronic kidney disease not receiving dialysis?

AIMSnIron metabolism is an important factor of anemia in chronic kidney disease (CKD). Hepcidin is a regulator of iron homeostasis and has a major role in the anemia of chronic disease (ACD). Oxidative stress (OS) is also associated with iron metabolism. However, the clinical utility of hepcidin, especially its association with OS, in CKD patients not receiving dialysis is still unclear.nnnMETHODSnWe recruited 117 patients (62 ± 15 years, 85 males, and median estimated glomerular filtration rate (eGFR) 22 ml/min/1.73 m2) with CKD not receiving dialysis. Serum 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of DNA oxidative injury, and serum hepcidin-25 were measured by ELISA and by liquid chromatography tandem mass spectrometry, respectively.nnnRESULTSnHepcidin-25 was associated positively with ferritin, high-sensitive C-reactive protein (hsCRP) and 8-OHdG, and negatively with eGFR and hemoglobin. Sex, oral iron, hemoglobin, transferrin saturation (TSAT), ferritin, and hsCRP were independently associated with hepcidin-25 in a multiple regression model. In contrast, neither eGFR nor 8-OHdG independently affected hepcidin- 25.nnnCONCLUSIONSnThe close association between hepcidin and serum ferritin, oral iron and hsCRP indicates that it plays a key role in the pathogenesis of anemia in patients with CKD not receiving dialysis. In contrast, effects of eGFR and OS were not apparent.

Pressure-length loop in the ischemic segment during left circumflex coronary artery stenosis and its modification by afterload reducing in excised perfused canine hearts

SummaryBy using excised perfused heart preparations, we investigated the regional myocardial functions in the presence of a flow-limiting coronary stenosis of the left circumflex coronary artery (LCX) (approximately a 50% flow reduction of pre-ischemic control), as well as global cardiac functions during afterload reducing, while keeping left ventricular end-diastolic pressure (LVEDP) and heart rate constant. After inducing the LCX stenosis, cardiac output (CO), peak left ventricular pressure (peak LVP) and stroke work (SW) decreased from pre-ischemic control values, i.e., 81.1±3.2%, p<0.005, 88.1±3.8%, p<0.02 and 72.2±5.7%, p<0.005, respectively (n=7), whereas pressure-length (P-L) loop areas changed as follows; ischemic control values of the left anterior descending coronary artery (LAD) and LCX regions were 96.6±6.0%, n.s. and 72.6±9.0% of pre-ischemic control, p<0.02, respectively.Following afterload reducing with LCX stenosis, CO increased gradually, while the ischemic regional function started to further aggravate, and the initial point of further ischemic aggravation obtained in this experiment occurred at 63.5±6.9 mm Hg of mean aortic pressure (AoP). These results suggested that the increase of total cardiac function such as CO following afterload reducing was probably induced at the expense of aggravated regional ischemia. Therefore it was concluded that the treatment of ischemic myocardium by reducing afterload pressure should be done very carefully.

Combined therapy with peritoneal dialysis and hemodialysis: a multicenter retrospective observational cohort study in Japan.

Background/Aims: Combining peritoneal dialysis (PD) and hemodialysis (HD) has been common treatment option in Japan. Methods: In this retrospective, multicenter, observational study, the clinical characteristics and outcomes of 104 patients (57 w 11 years, males 72%) who had switched from PD alone to combined therapy with PD and HD were studied. Clinical parameters were measured at baseline and after 3 months of combined therapy. Results: At baseline, urine volume, dialysate-to-plasma ratio of creatinine (D/P Cr), and total Kt/V were 150 ml/day (range: 0-2,000 ml/day), 0.67 w 0.11, and 1.8 w 0.4, respectively. During the first 3 months of combined therapy, body weight, urine volume, serum creatinine level, and D/P Cr decreased, whereas hemoglobin levels increased. Conclusions: In patients where PD does not result in acceptable outcomes, combined therapy with PD and HD may have potential benefits in terms of dialysis adequacy and hydration status. Video Journal Club “Cappuccino with Claudio Ronco” at http://www.karger.com/?doi=368389 i 2014 S. Karger AG, Basel

Effects of afterload elevation on the ischemic myocardium in isolated, paced canine heart with partial coronary stenosis

The effect of afterload elevation on the ischemic myocardium was examined in an isolated, paced canine heart with a partial coronary stenosis. The coronary blood flow of the left circumflex coronary artery was reduced to approximately one-third of the values before stenosis. The left circumflex coronary stenosis produced a decrease in global ventricular function, a decrease in systolic shortening and deviation of the ST-segment of the epicardial electrocardiogram and an increase in myocardial carbon dioxide (CO2) tension of the ischemic region. Then, afterload elevation with constant preload decreased the myocardial CO2 tension and improved the ST-segment deviation of the ischemic myocardium. Mechanical function, estimated by the relation between mean aortic pressure and systolic shortening, also improved with elevation of mean aortic pressure. In contrast, afterload elevation combined with preload elevation did not improve ischemic injury, as estimated by myocardial CO2 tension, and did not improve ST-segment deviation or mechanical function despite an increase in left circumflex coronary flow. These results suggest that the elevation of afterload pressure under constant preload improves ischemia produced by a partial coronary stenosis due to increased coronary blood supply; however, the preload elevation counterbalances the beneficial effects of afterload elevation.