2018 Korean Society of Hypertension Guidelines for the management of hypertension: part II-diagnosis and treatment of hypertension

The standardized techniques of blood pressure (BP) measurement in the clinic are emphasized and it is recommended to replace the mercury sphygmomanometer by a non-mercury sphygmomanometer. Out-of-office BP measurement using home BP monitoring (HBPM) or ambulatory BP monitoring (ABPM) and even automated office BP (AOBP) are recommended to correctly measure the patient’s genuine BP. Hypertension (HTN) treatment should be individualized based on cardiovascular (CV) risk and the level of BP. Based on the recent clinical study data proving benefits of intensive BP lowering in the high risk patients, the revised guideline recommends the more intensive BP lowering in high risk patients including the elderly population. Lifestyle modifications, mostly low salt diet and weight reduction, are strongly recommended in the population with elevated BP and prehypertension and all hypertensive patients. In patients with BP higher than 160/100 mmHg or more than 20/10 mmHg above the target BP, two drugs can be prescribed in combination to maximize the antihypertensive effect and to achieve rapid BP control. Especially, single pill combination drugs have multiple benefits, including maximizing reduction of BP, minimizing adverse effects, increasing adherence, and preventing cardiovascular disease (CVD) and target organ damage.

Prolonged insulin independence after islet allotransplants in recipients with type 1 diabetes

We sought to determine the long-term outcomes in type 1 diabetic recipients of intraportal alloislet transplants on a modified immunosuppressive protocol. Six recipients with hypoglycemia unawareness received one to two islet infusions. Induction therapy was with antithymocyte globulin (ATG) plus etanercept for tumor necrosis factor-alpha blockade. Recipients received cyclosporine and everolimus for maintenance immunosuppression for the first year posttransplant, with mycophenolic acid or mycophenolate mofetil subsequently substituted for everolimus. Recipients have been followed for 1173 +/- 270 days since their last infusion for islet graft function (insulin independence, hemoglobin A(1c) levels and C-peptide production) and for adverse events associated with the study protocol. Of the six recipients, five were insulin-independent at 1 year, and four continue to be insulin-independent at a mean of 3.4 +/- 0.4 years posttransplant. None of the six recipients experienced recurrence of severe hypoglycemia. Measured glomerular filtration rate decreased from 110.5 +/- 21.2 mL/min/1.73 m(2) pretransplant to 82.6 +/-19.1 mL/min/1.73 m(2) at 1 year posttransplant. In conclusion, islet transplants restored insulin independence for a mean of >3 years in four of six recipients treated with ATG and etanercept induction therapy and with cyclosporine and, initially, everolimus for maintenance. Our results suggest this immunosuppressive protocol may allow long-term graft survival.

Excess protein O-GlcNAcylation and the progression of diabetic cardiomyopathy

We examined the role that enzymatic protein O-GlcNAcylation plays in the development of diabetic cardiomyopathy in a mouse model of Type 2 diabetes mellitus (DM2). Mice injected with low-dose streptozotocin and fed a high-fat diet developed mild hyperglycemia and obesity consistent with DM2. Studies were performed from 1 to 6 mo after initiating the DM2 protocol. After 1 mo, DM2 mice showed increased body weight, impaired fasting blood glucose, and hyperinsulinemia. Echocardiographic evaluation revealed left ventricular diastolic dysfunction by 2 mo and O-GlcNAcylation of several cardiac proteins and of nuclear transcription factor Sp1. By 4 mo, systolic dysfunction was observed and sarcoplasmic reticulum Ca(2+) ATPase expression decreased by 50%. Fibrosis was not observed at any timepoint in DM2 mice. Levels of the rate-limiting enzyme of the hexosamine biosynthetic pathway, glutamine:fructose-6-phosphate amidotransferase (GFAT) were increased as early as 2 mo. Fatty acids, which are elevated in DM2 mice, can possibly be linked to excessive protein O-GlcNAcylation levels, as cultured cardiac myocytes in normal glucose treated with oleic acid showed increased O-GlcNAcylation and GFAT levels. These data indicate that the early onset of diastolic dysfunction followed by the loss of systolic function, in the absence of cardiac hypertrophy or fibrosis, is associated with increased cardiac protein O-GlcNAcylation and increased O-GlcNAcylation levels of key calcium-handling proteins. A link between excessive protein O-GlcNAcylation and cardiac dysfunction is further supported by results showing that reducing O-GlcNAcylation by O-GlcNAcase overexpression improved cardiac function in the diabetic mouse. In addition, fatty acids play a role in stimulating excess O-GlcNAcylation. The nature and time course of changes observed in cardiac function suggest that protein O-GlcNAcylation plays a mechanistic role in the triggering of diabetic cardiomyopathy in DM2.

Effects of Sacubitril/Valsartan (LCZ696) on Natriuresis, Diuresis, Blood Pressures, and NT-proBNP in Salt-Sensitive Hypertension

Salt-sensitive hypertension (SSH) is characterized by impaired sodium excretion and subnormal vasodilatory response to salt loading. Sacubitril/valsartan (LCZ696) was hypothesized to increase natriuresis and diuresis and result in superior blood pressure control compared with valsartan in Asian patients with SSH. In this randomized, double-blind, crossover study, 72 patients with SSH received sacubitril/valsartan 400 mg and valsartan 320 mg once daily for 4 weeks each. SSH was diagnosed if the mean arterial pressure increased by ≥10% when patients switched from low (50 mmol/d) to high (320 mmol/d) sodium diet. The primary outcome was cumulative 6- and 24-hour sodium excretion after first dose administration. Compared with valsartan, sacubitril/valsartan was associated with a significant increase in natriuresis (adjusted treatment difference: 24.5 mmol/6 hours, 50.3 mmol/24 hours, both P <0.001) and diuresis (adjusted treatment difference: 291.2 mL/6 hours, P <0.001; 356.4 mL/24 hours, P =0.002) on day 1, but not on day 28, and greater reductions in office and ambulatory blood pressure on day 28. Despite morning dosing of both drugs, ambulatory blood pressure reductions were more pronounced at nighttime than at daytime or the 24-hour average. Compared with valsartan, sacubitril/valsartan significantly reduced N-terminal pro B-type natriuretic peptide levels on day 28 (adjusted treatment difference: −20%; P =0.001). Sacubitril/valsartan and valsartan were safe and well tolerated with no significant changes in body weight or serum sodium and potassium levels with either treatments. In conclusion, sacubitril/valsartan compared with valsartan was associated with short-term increases in natriuresis and diuresis, superior office and ambulatory blood pressure control, and significantly reduced N-terminal pro B-type natriuretic peptide levels in Asian patients with SSH.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01681576.

Effect of aminoguanidine on lipid peroxidation in streptozotocin-induced diabetic rats

Diabetes mellitus is postulated to be associated with increased lipid peroxidation, which may contribute to vascular complications. One potential mechanism of the increased lipid peroxidation in diabetes is lipid-linked advanced glycosylation and oxidation. Aminoguanidine (AMGN), the prototype inhibitor of advanced glycosylation end product (AGE) formation, has been recently shown to prevent oxidative modification of low-density lipoprotein (LDL) in vitro at a moderate concentration. It is unknown whether AMGN may act as an antioxidant against lipid peroxidation under hyperglycemia in vivo. To investigate the in vivo effect of AMGN on lipid peroxidation in diabetes, we administered AMGN (1 g/L in drinking water) or vitamin E (400 mg/d for 5 d/wk) to streptozotocin (STZ)-induced diabetic rats for 9 weeks and measured plasma lipid hydroperoxides by ferrous oxidation with xylenol orange II (FOX method) and red blood cell (RBC) membrane malondialdehyde (MDA) and related aldehydes as thiobarbituric acid-reactive substances (TBARS). Plasma lipid hydroperoxide was higher in STZ-induced diabetic rats versus control rats (mean +/- SD, 7.53 +/- 2.03 v 5.62 +/- 0.44 micromol/L, P < .05; n = 8 to 14). RBC membrane TBARS were also higher in STZ-induced diabetic rats than in control rats (2.67 +/- 0.46 v 1.81 +/- 0.19 nmol/mL, P < .05). Plasma lipid hydroperoxide was lower in AMGN-treated (6.23 +/- 0.59 micromol/L, P < .05) and vitamin E-treated (5.29 +/- 0.27 micromol/L, P < .05) diabetic rats than in untreated diabetic rats. RBC membrane TBARS were also lower in AMGN-treated (1.93 +/- 0.12 nmol/mL, P < .05) diabetic rats than in untreated diabetic rats. There was no significant difference in plasma glucose, cholesterol, and triglyceride levels among diabetic groups. Although the mechanism(s) of action of AMGN on lipid peroxidation in vivo should be studied further, these results suggest that AMGN may have an additional beneficial effect as an antioxidant against lipid peroxidation in a prevention trial for diabetic vascular complications.

2018 Korean Society of Hypertension guidelines for the management of hypertension: part I-epidemiology of hypertension

The Korean Society of Hypertension guideline defines hypertension as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg, where the effectiveness of pharmacological treatment has been established. It is confirmed that higher blood pressure levels are associated with increased risk of cardiovascular disease and mortality also in the Korean population. About one third of Korean adults aged 30 years or older are estimated to have hypertension, and the prevalence of hypertension gradually increases as the age increases. The awareness, treatment, and control rates of hypertension are generally improving in Korea, but more efforts are required to increase awareness and treatment among younger patients with hypertension and to improve lifestyle modification compliance at all ages. More studies are required to determine the magnitude and impact of white coat hypertension and masked hypertension in the Korean population.

Noninvasive assessment of myocardial inflammation by cardiovascular magnetic resonance in a rat model of experimental autoimmune myocarditis

BACKGROUND

Limited availability of noninvasive and biologically precise diagnostic tools poses a challenge for the evaluation and management of patients with myocarditis.

METHODS AND RESULTS

The feasibility of cardiovascular magnetic resonance (CMR) imaging with magneto-fluorescent nanoparticles (MNPs) for detection of myocarditis and its effectiveness in discriminating inflammation grades were assessed in experimental autoimmune myocarditis (EAM) (n=65) and control (n=10) rats. After undergoing CMR, rats were administered with MNPs, followed by a second CMR 24 hours later. Head-to-head comparison of MNP-CMR with T(2)-weighted, early and late gadolinium enhancement CMR was performed in additional EAM (n=10) and control (n=5) rats. Contrast-to-noise ratios were measured and compared between groups. Flow cytometry and microscopy demonstrated that infiltrating inflammatory cells engulfed MNPs, resulting in altered myocardial T(2)* effect. Changes in contrast-to-noise ratio between pre- and post-MNP CMR were significantly greater in EAM rats (1.08 ± 0.10 versus 0.48 ± 0.20; P<0.001). In addition, contrast-to-noise ratio measurement in MNP-CMR clearly detected the extent of inflammation (P<0.001) except for mild inflammation. Compared with conventional CMR, MNP-CMR provided better image contrast (CNR change 8% versus 46%, P<0.001) and detectability of focal myocardial inflammation. Notably, MNP-CMR successfully tracked the evolution of myocardial inflammation in the same EAM rats.

CONCLUSIONS

Magneto-fluorescent nanoparticle CMR permitted effective visualization of myocardial inflammatory cellular infiltrates and distinction of the extent of inflammation compared with conventional CMR in a preclinical model of EAM. Magneto-fluorescent nanoparticle CMR performs best in EAM rats with at least moderate inflammatory response.

Relation between C-reactive protein, homocysteine levels, fibrinogen, and lipoprotein levels and leukocyte and platelet counts, and 10-year risk for cardiovascular disease among healthy adults in the USA

The association between systemic inflammation and the estimated 10-year risk for coronary artery disease (CAD) according to the Framingham risk score is largely unknown. In this study, 6,371 participants in the Third National Health and Nutrition Examination Survey (NHANES III) aged 40 to 79 years, who had no histories of heart attack, stroke, peripheral artery disease, or diabetes mellitus, were categorized into groups at low (<10%), intermediate (10% to 20%), and high (>20%) risk according to 10-year risk for CAD, calculated using the Framingham risk score modified by the National Cholesterol Education Program Adult Treatment Panel III. After adjustments for age, gender, race, body mass index, and co-morbidities, participants at high risk were more likely to have elevated circulating C-reactive protein levels (>/=2.2 mg/L: adjusted odds ratio [OR] 1.61, 95% confidence interval [CI] 1.30 to 2.01, p <0.0001; >10.0 mg/L: OR 1.41, 95% CI 1.03 to 1.93, p = 0.034). The high-risk group had circulating fibrinogen, homocysteine, leukocyte, and platelet levels that were 20.98 mg/dl (95% CI 12.53 to 29.43, p <0.0001), 1.54 mumol/L (95% CI 0.76 to 2.32, p = 0.002), 0.90 mumol/L (95% CI 0.36 to 1.43, p = 0.001), 910/microl (95% CI 670 to 1,160, p <0.0001), and 10,220/microl (95% CI 2,830 to 17,610, p <0.0001) higher, respectively, than in those in the low-risk group. There was also a dose-dependent increase in circulating levels of inflammatory markers across the categories of CAD risk. In conclusion, these findings indicate that low-grade systemic inflammation and hyperhomocysteinemia were present in participants with high 10-year risk for CAD.

Metabolically obese status with normal weight is associated with both the prevalence and severity of angiographic coronary artery disease

OBJECTIVE

We evaluated prevalence and severity of angiographic coronary artery disease (CAD) according to groups by metabolically obese (MO) and/or weight status.

MATERIAL/METHODS

Normal weight was defined as body mass index (BMI, kg/m²)<25 and obesity was defined as BMI≥25. The MO was determined using the National Cholesterol Education Program-Adult Treatment Panel III classification with Korean-specific cutoffs for abdominal obesity. Therefore, a total of 856 subjects were categorized as follows: (1) metabolically healthy and normal weight (MHNW); (2) metabolically obese but normal weight (MONW); (3) metabolically healthy but obese (MHO); and (4) metabolically abnormally obese (MAO). The presence of obstructive lesion≥50% of coronary artery was considered as an angiographic CAD and the Gensini scoring system was used for the severity.

RESULTS

MONW or MO showed a higher prevalence of CAD than MHNW or non-MO after adjustment for age and sex, respectively (MONW, odds ratio [OR]=1.69, 95% confidence interval [CI]: 1.13-2.51 and MO, OR=1.44, 95% CI: 1.09-1.91). In subjects without diabetes mellitus (DM), MONW or MO showed a marginally higher prevalence of CAD (MONW, OR=1.58, 95% CI: 0.96-2.61 and MO, OR=1.41, 95% CI: 0.96-2.08). MONW was independently associated with a higher severity of angiographic CAD than MHNW after age, sex, glomerular filtration rate, smoking status, high sensitive C-reactive protein, and use of anti-platelet and anti-angina drugs (β=0.118, P=0.005). And MO was associated with a higher severity of angiographic CAD than non-MO after adjustment for age and sex (β=0.077, P=0.024). The above associations were also consistent in subjects without DM (MONW, β=0.147, P=0.003 and MO, β=0.129, P=0.005).

CONCLUSIONS

MONW or MO is associated with both the prevalence and severity of angiographic CAD after adjustment for age and sex and MONW is independently associated with the severity of angiographic CAD irrespective of DM. Therefore, subjects with MO but normal weight (MONW) should be carefully examined for angiographic CAD.

Decaffeinated green tea extract improves hypertension and insulin resistance in a rat model of metabolic syndrome

BACKGROUND

Oxidative stress and endothelial dysfunction are closely associated with hypertension and insulin resistance (IR) in metabolic syndrome (MetS). It is still controversial whether green tea extract (GTE) may have blood pressure (BP) lowering effect. Decaffeinated GTE might be presumed to have strong antioxidative effect and BP-lowering effect as compared with catechins. Thus we investigated whether decaffeinated-GTE could attenuate hypertension and IR by improving endothelial dysfunction and reducing oxidative stress in a rat model of MetS.

METHODS AND RESULTS

20 Otsuka Long-Evans Tokushima Fatty (OLETF) rats at 13 weeks old, MetS rats, were randomized into a saline treated group (OLETF; n = 10) and a group treated with decaffeinated-GTE (25 mg/kg/day) (GTE-OLETF; n = 10). Intraperitoneal glucose tolerance tests and BP measurements were performed at 13 and 25 weeks. Decaffeinated-GTE significantly reduced BP (OLETF vs. GTE-OLETF; 130 ± 7 vs. 121 ± 3 mmHg, p = 0.01), fasting/postprandial 2 h glucose (141 ± 18/159 ± 13 vs. 115 ± 7/132 ± 16 mg/dL, p = 0.009/0.002) and insulin levels (4.8 ± 2.3 vs. 2.4 ± 1.3 ng/mL, p < 0.001). Decaffeinated-GTE significantly reduced vascular reactive oxygen species (ROS) formation and NADPH oxidase activity, and improved endothelium dependent relaxation in the thoracic aorta of OLETF rats. Decaffeinated-GTE also suppressed the expression of p47 and p22phox (NADPH oxidase subunits) in the immunohistochemical staining, and stimulated phosphorylation of endothelial nitric oxide synthase (eNOS) and Akt in the immunoblotting of aortas.

CONCLUSIONS

Decaffeinated-GTE reduced the formation of ROS and NADPH oxidase activity and stimulated phosphorylation of eNOS and Akt in the aorta of a rat model of MetS, which resulted in improved endothelial dysfunction and IR, and eventually lowered BP.

Statins and renin-angiotensin system inhibitor combination treatment to prevent cardiovascular disease

Hypercholesterolemia and hypertension are common risk factors for cardiovascular disease (CVD). Updated guidelines emphasize target reductions of overall cardiovascular risks. Experimental studies have shown reciprocal relationships between insulin resistance (IR) and endothelial dysfunction. Hypercholesterolemia and hypertension have a synergistic deleterious effect on IR and endothelial dysfunction. Unregulated renin-angiotensin system (RAS) is important in the pathogenesis of atherosclerosis and hypertension. Various strategies with different classes of antihypertensive medications to reach target goals have failed to reduce residual CVD risk further. Of interest, treating moderate cholesterol elevations with low-dose statins in hypertensive patients reduced CVD risk by 35-40% further. Therefore, statins are important in reducing CVD risk. Unfortunately, statin therapy causes IR and increases the risk of type 2 diabetes mellitus. RAS inhibitors improve both endothelial dysfunction and IR. Further, cross-talk between hypercholesterolemia and RAS exists at multiple steps of IR and endothelial dysfunction. In this regard, combined therapy with statins and RAS inhibitors demonstrates additive/synergistic effects on endothelial dysfunction and IR in addition to lowering cholesterol levels and blood pressure when compared with either monotherapy in patients. This is mediated by both distinct and interrelated mechanisms. Therefore, combined therapy with statins and RAS inhibitors may be important in developing optimal management strategies in patients with hypertension, hypercholesterolemia, diabetes, metabolic syndrome, or obesity to prevent CVD.  

The Glu298Asp polymorphism in the endothelial nitric oxide synthase gene is strongly associated with coronary spasm

BACKGROUND

Coronary spasm seems to be associated with coronary nitric oxide deficiency.

OBJECTIVES

We investigated whether the Glu298Asp polymorphism in the endothelial nitric oxide synthase (eNOS) gene is a definite risk factor for coronary spasm and whether diffuse spasm involving normal-looking coronary artery correlates significantly with the Glu298Asp polymorphism, in contrast with focal spasm superimposed on an atherosclerotic plaque.

METHODS

A polymerase chain reaction followed by restriction fragment length polymorphism analysis was performed in 118 control participants and in 102 patients with variant angina and a similar degree of atherosclerotic burden. Patients with coronary spasm were divided into diffuse spasm and focal spasm subgroups according to morphological criteria.

RESULTS

There was a significantly higher incidence of the Glu298Asp polymorphism in the coronary spasm group than in the control group (21.5% compared with 8.5%, P=0.006). Multiple logistic regression analysis using risk factors and the Glu298Asp polymorphism showed that the most important predictive factor for coronary spasm was the Glu298Asp polymorphism (odds ratio 2.83, 95% confidence interval 1.25-6.41, P=0.009). The diffuse spasm subgroup had a significantly higher frequency of the Glu298Asp polymorphism than the control group (25.9% compared with 8.5%, P=0.002). However, the focal spasm subgroup did not differ from the control group in the frequency of Glu298Asp polymorphism.

CONCLUSION

The Glu298Asp polymorphism in the eNOS gene is a definite risk factor for coronary spasm, especially for diffuse coronary spasm. This result supports the notion that diffuse coronary spasm is significantly associated with endothelial dysfunction, in contrast to focal spasm.

2018 Korean society of hypertension guidelines for the management of hypertension: part III-hypertension in special situations

Treatment of hypertension improves cardiovascular, renal, and cerebrovascular outcomes. However, the benefit of treatment may be different according to the patients' characteristics. Additionally, the target blood pressure or initial drug choice should be customized according to the special conditions of the hypertensive patients. In this part III, we reviewed previous data and presented recommendations for some special populations such as diabetes mellitus, chronic kidney disease, elderly people, and cardio-cerebrovascular disease.

Spatial and temporal expression, and statin responsiveness of galectin-1 and galectin-3 in murine atherosclerosis

Background and Objectives

Existing data on the spatiotemporal expression patterns of a variety of galectins in murine atherosclerosis are limited. We investigated the expression levels of galectins, and their in vivo spatiotemporal expression patterns and statin responsiveness in the inflamed atherosclerotic plaques of apolipoprotein E (apoE)^-/- mice.

Materials and Methods

Galectins expression patterns in aortic atherosclerotic plaques and serum galectin-3 levels were investigated in 26-week-old apoE^-/- (n=6) and C57BL/6 mice (n=9). To investigate the spatial and temporal patterns of galectin-1 and galectin-3 in plaques, high-cholesterol diet-fed 26-week-old (n=12) and 36-week-old apoE^-/- mice (n=6) were sacrificed and their aortas were examined for galectins' expression using immunoblot analysis and immunohistochemical stain. 36-week-old apoE^-/- mice were treated with atorvastatin (n=3, 0.57 mg/kg/day) for the evaluation of its effect on aortic galectins' expression.

Results

Immunoblot analyses showed that galectin-1 and galectin-3 were the predominant galectins expressed in murine atherosclerosis. The serum galectin-3 level was significantly higher in apoE^-/- mice (p<0.001). While galectin-1 was weakly expressed in both intimal plaques and the media of atherosclerotic aortas, galectin-3 was heavily and exclusively accumulated in intimal plaques. Galectin-3 distribution was colocalized with plaque macrophages' distribution (r=0.66). As the degree of plaque extent and inflammation increased, the intraplaque galectin-3 expression levels proportionally elevated (p<0.01 vs. baseline), whereas galectin-1 expression had not elevated (p=0.14 vs. baseline). Atorvastatin treatment markedly reduced intraplaque galectin-3 and macrophage signals (p<0.001 vs. baseline), whereas it failed to reduce galectin-1 expression in the aortas.

Conclusion

Galectin-3 is the predominant gal and is colocalized with macrophages within atherosclerotic plaques. Intraplaque galectin-3 expression reflects the degree of plaque inflammation.

Studies on autoimmunity for initiation of beta-cell destruction. VI. Macrophages essential for development of beta-cell-specific cytotoxic effectors and insulitis in NOD mice

NOD mice were treated with silica (which is selectively toxic to macrophages) from 4 or 20.5 wk of age. Syngeneic neonatal pancreases were transplanted into the renal subcapsular space of the NOD mice at 21 wk of age. Silica treatment was continued until 24 wk of age, and then the mice were killed for examination of islet morphology. Neither the islets in transplanted pancreases nor the host pancreatic islets from the early long-term silica-treated animals revealed insulitis. In contrast, most of the islets in transplanted pancreases from the late short-term silica-treated animals showed severe insulitis and beta-cell necrosis, as did the host islets. A further experiment was performed to compare the effect of late short-term silica treatment with that of anti-L3T4-antibody treatment of the same time and duration. In contrast to the late short-term silica-treated animals, the transplanted pancreases in the anti-L3T4-antibody-treated animals revealed intact islets, although most of the host islets showed insulitis. The control group, which received no treatment but did receive neonatal pancreases, revealed severe insulitis and beta-cell necrosis of both transplanted and host islets. These results suggest that early macrophage depletion can abolish the development of beta-cell-specific immunologic effectors but that late macrophage depletion, after the development of insulitis, does not affect the destruction of beta-cells by preexisting effectors other than macrophages. We conclude that macrophages are essential for the development of beta-cell-specific cytotoxic effectors in the initial phase of insulitis in NOD mice.

Effect of preload on left atrial function: evaluated by tissue Doppler and strain imaging

AIMS

Both strain and strain rate (SR) measure the regional myocardial deformation and can assess phasic left atrial (LA) function. However, there is still a lack of evidence for their volume independency. In this study, strain and SR determined by tissue Doppler imaging were used to evaluate the effect of preload reduction in end-stage renal disease patients who were undergoing regular haemodialysis (HD).

METHODS AND RESULTS

Forty-one subjects who underwent transthoracic echocardiography just before and after HD were enrolled. LA strain was measured during late systole, and LA peak tissue velocity and SR were measured during systole and during early and late diastolic periods. The values of tissue velocity, strain, and SR were obtained in the basal septal, lateral, inferior, and anterior walls of the LA. The mean strain value was 23.89 ± 7.29% at baseline and decreased to 21.88 ± 5.85% after HD (P = 0.019). SR during systole (before HD 1.55 ± 0.40; after HD 1.38 ± 0.35, P = 0.001) and early diastole (before HD -1.41 ± 0.54; after HD -1.16 ± 0.45, P = 0.001) also changed. However, the acute preload change caused by HD did not affect the peak tissue velocity (before HD -6.34 ± 1.58 cm/s; after HD -6.46 ± 1.54 cm/s, P = 0.436) and the SR (before HD -1.36 ± 0.45/s; after HD -1.34 ± 0.29/s, P = 0.621) measured during late diastole.

CONCLUSION

Both tissue velocity and SR during late diastole, representing the contractile function of the LA, are relatively preload-independent parameters and are available for the evaluation of the LA function.

Viruses as a triggering factor of type 1 diabetes and genetic markers related to the susceptibility to the virus-associated diabetes

Type 1 diabetes results from the destruction of insulin-producing pancreatic beta cells. Genetic and environmental factors are implicated in the beta cell destruction. As environmental factors affecting the induction of type 1 diabetes, diabetogenic viruses, chemicals, toxins, and diet are likely candidates as either primary injurious agents of beta cells or triggering agents for the induction of autoimmunity. Regarding viruses as a triggering factor of type 1 diabetes, there are at least two different pathogenic mechanisms in virus-induced diabetes: cytolytic infection of beta cells, leading to their destruction, and triggering of autoimmunity, leading to the autoimmune-mediated destruction of beta cells. Since there is no correlation between the induction of antibodies to Coxsackie B viruses and the presence of islet cell autoantibodies in patients with type 1 diabetes, the induction of diabetes by Coxsackie B viruses may be due to cytolytic infection of beta cells rather than an autoimmune response. In contrast, rubella virus and cytomegalovirus (CMV) do appear to be somehow associated with autoimmune type 1 diabetes since there is a strong correlation between the presence of islet cell autoantibodies and persistent infections. Regarding genetic factors, there are distinct markers related to the susceptibility to Coxsackie B4 virus-associated type 1 diabetes and CMV-associated type 1 diabetes. Four specific DNA restriction endonuclease fragments (BamHI-DQ-beta 6.6, TaqI-DR-beta 4.3, TaqI-DR-beta 2.5 and TaqI-DR-beta 1.5 kb) are related to the susceptibility to Coxsackie B4 virus-associated type 1 diabetes while six specific DNA restriction endonuclease fragments (BamHI-DQ-alpha 12.5, -beta 3.7 and -beta 3.2 kb, TaqI-DQ-alpha 7.2, -beta 7.2 and -beta 5.4 kb) are related to the susceptibility to CMV-associated type 1 diabetes.

Not nondipping but nocturnal blood pressure predicts left ventricular hypertrophy in the essential hypertensive patients: the Korean Ambulatory Blood Pressure multicenter observational study

OBJECTIVE

The aim of this study was to investigate whether nocturnal blood pressure (BP), established on the basis of a single 24-h BP monitoring, is a stronger predictor of left ventricular hypertrophy (LVH) compared with nondipping status in the essential hypertensive patients.

METHODS

A total of 682 hypertensive patients (mean age 56.1 ± 14.5 years, 50.7% women) who underwent echocardiography were enrolled. 'Nondipping status' was defined as a nocturnal SBP fall less than 10% of daytime mean SBP. LVH was defined as a left ventricular mass index exceeding 54.0 g/m in men and 53.0 g/m in women. Each patient was categorized in three groups according to the total cardiovascular risk using 2007 European Society of Hypertension/ European Society of Cardiology guidelines as average or low, moderate, and high or very high added risk.

RESULTS

Among 682 participants, 184 (26.9%) showed LVH on echocardiography. The proportion of individuals with high or very high added cardiovascular risk profile was 356 (52.1%). In multiple logistic regression analysis, age 56 years at least [odds ratio (OR) 1.047, 95% confidence interval (CI) 1.031-1.063, P < 0.0001], female participants (OR 1.751, 95% CI 1.172-2.616, P = 0.0062), BMI higher than 24.6 kg/m (OR 1.178, 95% CI 1.110-1.250, P < 0.0001), smoking (OR 1.793, 95% CI 1.028-3.127, P = 0.0397), and nocturnal SBP at least 127 mmHg (OR 1.032, 95% CI 1.009-1.055, P = 0.0059) were significant independent predictors for LVH whereas nondipping was not (OR 0.857, 95% CI 0.481-1.528, P = 0.6013).

CONCLUSION

These findings suggest that nocturnal BP rather than nondipping may be a better predictor of LVH, especially in secondary or tertiary referral hospital setting targeting relatively high cardiovascular risk patients.

Relation Between Flow Reserve Capacity of Penetrating Intramyocardial Coronary Arteries and Myocardial Fibrosis in Hypertension: Study Using Transthoracic Doppler Echocardiography

OBJECTIVE

The purpose of this study was to compare coronary flow reserve (CFR) capacity of penetrating intramyocardial coronary artery (PICA) using transthoracic Doppler echocardiography and biochemical marker of myocardial fibrosis in hypertension (HTN).

METHODS

In 58 patients (male:female ratio = 31:27; mean age 47 +/- 9 years) with chest pain and normal coronary angiogram findings, the width of color Doppler signal and peak diastolic velocity of PICA flow were measured in the myocardium just beneath the apical impulse window using transthoracic Doppler echocardiography. PICA-CFR and PICA-width ratio were calculated as the ratio of hyperemic to baseline peak diastolic velocity and as the ratio of hyperemic to baseline width after the adenosine infusion (140 mug/kg/min), respectively. Serum carboxy-terminal propeptide of procollagen type I, as a biochemical marker, was measured and patients were divided into 3 groups: 19 with HTN and PICA-CFR less than 2.0 (group A); 23 with HTN and PICA-CFR of 2.0 or more (group B); and 16 who were normotensive with PICA-CFR of 2.0 or more (group C).

RESULTS

Baseline peak diastolic velocity for group A was higher than the other two groups (P < .005 vs groups B and C). PICA-width ratio was higher than the other two groups (P < .005 vs groups B and C). Serum propeptide of type I was 137.1 +/- 16.6 ng/mL in group A, 96.2 +/- 13.7 ng/mL in group B, and 78.8 +/- 11.2 ng/mL in group C (P < .0001 vs group B and group C). PICA-CFR was closely related to serum propeptide of type I (P < .001, r = -0.723).

CONCLUSION

The impaired PICA-CFR is related to myocardial fibrosis in patients with HTN, chest pain, and normal coronary angiogram results.