East Asians Variant Mitochondrial Aldehyde Dehydrogenase 2 Genotype Exacerbates Nitrate Tolerance in Patients With Coronary Spastic Angina.

BACKGROUND: Aldehyde dehydrogenase 2 (ALDH2) plays a central role in the biotransformation of glyceryl trinitrate (GTN) or nitroglycerin, which is widely used for the treatment of coronary artery disease (CAD). The deficient variant ALDH2 genotype (ALDH2*2) is prevalent among East Asians. This study examined whether there are differences in nitroglycerine-mediated dilation (NMD) and flow-mediated dilation (FMD) response between wildALDH2*1/*1and variantALDH2*2patients with CAD.Methods and Results:The study subjects comprised 55 coronary spastic angina (CSA) patients, confirmed by coronary angiography and intracoronary injection of acetylcholine (42 men and 13 women, mean age 68.0±9.0 years). They underwent NMD and FMD tests in the morning before and after continuous transdermal GTN administration for 48 h. NMD was lower at baseline inALDH2*2than in theALDH2*1/*1group (P=0.0499) and decreased significantly in both groups (P<0.0001 and P<0.0001, respectively) after GTN, with significantly lower levels in theALDH2*2group (P=0.0002). FMD decreased significantly in bothALDH2*1/*1andALDH2*2groups (P<0.0001and P=0.0002, respectively) after continuous GTN administration, with no significant differences between the 2 groups both before and after GTN. CONCLUSIONS: Continuous administration of GTN produced endothelial dysfunction as well as nitrate tolerance in bothALDH2*1/1andALDH2*2patients with CSA.ALDH2*2attenuated GTN response and exacerbated GTN tolerance, but not endothelial dysfunction, as compared toALDH2*1/*1in patients with CSA.

Sex Differences in Heart Failure With Preserved Ejection Fraction Reflected by B-type Natriuretic Peptide Level.

BACKGROUND: Prevalence of heart failure with preserved ejection fraction (HFpEF) increases with advancing age, particularly among women. Plasma levels of B-type natriuretic peptide (BNP), a surrogate marker of heart failure, have consistently been shown to be higher in women in the general populations. Whether BNP levels differ as per the sex of HFpEF patients remains largely unknown. MATERIALS AND METHODS: The study subjects were 733 HFpEF patients (204 men and 529 women, aged 80.9 ± 9.6 years) who underwent echocardiography and routine clinical examination, including plasma BNP level evaluation. These parameters were compared between women and men. RESULTS: Plasma levels of BNP were significantly lower in women than in men (104 [61, 192] versus 133 [78, 255] pg/mL, P < 0.001), just as hemoglobin, atrial fibrillation, diabetes mellitus, beta-blockers, left ventricular diastolic dimension, left ventricular mass index, left ventricular eccentric hypertrophy and left atrial dimension were. Age, systolic blood pressure, pulse pressure, heart rate, left ventricular relative wall thickness, left ventricular ejection fraction and left ventricular concentric hypertrophy were higher in women than in men. Multiple regression analyses revealed that left ventricular mass index, body mass index, the ratio of early diastolic mitral flow velocity to tissue annular motion velocity divided by left ventricular diastolic dimension, estimated glomerular filtration rate, beta-blockers, left atrial dimensions, female sex and atrial fibrillation were significant predictors for BNP levels (t = 5.41, P < 0.001; t = -4.06, P < 0.001; t = 3.76, P < 0.001; t = -3.68, P < 0.001; t = 3.32, P = 0.001; t = 3.11, P = 0.002; t = -3.07, P = 0.002; and t = 2.65, P = 0.008, respectively). CONCLUSIONS: Plasma BNP levels were lower in women and were related to left ventricular concentric remodeling and hypertrophy among HFpEF patients, contrary to those in the general population.

The diabetic heart utilizes ketone bodies as an energy source.

BACKGROUND: Diabetic heart is characterized by failure of insulin to increase glucose uptake and increasingly relies on free fatty acids (FFAs) as a source of fuel in animal models. However, it is not well known how cardiac energy metabolism is altered in diabetic hearts in humans. We examined cardiac fuel metabolism in the diabetics as compared to non-diabetics who underwent cardiac catheterization for heart diseases. MATERIAL AND METHODS: The study subjects comprised 81 patients (male 55, female 26, average age 63.0±10.0years) who underwent the cardiac catheterization for heart diseases. Thirty-six patients were diagnosed as diabetics (diabetic group) and 45 as non-diabetics (non-diabetic group). Blood samplings were done in both the aortic root (Ao) and coronary sinus (CS) simultaneously and the plasma levels of FFAs, glucose, lactate, pyruvate, total ketone bodies and ß-hydroxybutyrate were measured and compared between the two groups. RESULTS: The myocardial uptake of glucose, lactate and pyruvate were decreased, whereas those of total ketone bodies, ß-hydroxybutyrate and acetoacetate were increased in the diabetics as compared to the non-diabetics. However, the myocardial uptakes of FFAs were not significantly increased in the diabetics as compared to the non-diabetics. CONCLUSIONS: Cardiac uptakes of carbohydrate (glucose, lactate and pyruvate) were decreased, whereas those of total ketone bodies and ß-hydroxybutyrate were increased in the diabetics as compared to the non-diabetics in humans. Ketone bodies therefore are utilized as an energy source partially replacing glucose in the human diabetic heart.

B-Type Natriuretic Peptide in Heart Failure With Preserved Ejection Fraction　- Relevance to Age-Related Left Ventricular Modeling in Japanese.

BACKGROUND: Heart failure (HF) with preserved ejection fraction (HFpEF) is increasing with aging of the population. Plasma levels of B-type natriuretic peptide (BNP) increase in proportion to the severity of left ventricular (LV) dysfunction. The object of this study was to examine the plasma levels of BNP in HFpEF to better understand the pathogenesis of HFpEF as compared with HF with reduced EF (HFrEF).Methods and Results:The study subjects comprised 468 HFpEF patients (158 men, 310 women, mean age 81.3±9.6 years) and 126 HFrEF patients (77 men, 49 women, mean age 75.4±12.0 years) who underwent echocardiography and routine clinical examinations including plasma BNP. Age, female prevalence, systolic blood pressure and pulse pressure were higher in the HFpEF patients than in the HFrEF patients (P<0.0001, P<0.001, P<0.0001, and P<0.0001, respectively). Plasma BNP levels, LV diastolic dimensions, and LV mass index (LVMI) were lower (P<0.0001, P<0.0001, and P<0.0001, respectively), while relative wall thickness was higher (P<0.0001) in the HFpEF patients than in the HFrEF patients. Multiple regression analysis revealed that LVMI, EF, plasma levels of albumin, C-reactive protein, and uric acid were the predictors of BNP levels (P<0.001, P<0.001, P=0.009, P=0.012, and P=0.018, respectively). CONCLUSIONS: Plasma BNP levels were lower and related to aging-related LV concentric remodeling/hypertrophy in HFpEF patients as compared with HFrEF patients, who were associated predominantly with eccentric LV hypertrophy.

East asian variant of aldehyde dehydrogenase 2 is associated with coronary spastic angina: possible roles of reactive aldehydes and implications of alcohol flushing syndrome.

BACKGROUND: Coronary spastic angina (CSA) is a common disease among East Asians, including Japanese. The prevalence of alcohol flushing syndrome associated with deficient activity of the variant aldehyde dehydrogenase 2 (ALDH2*2) genotype is prevalent among East Asians. We examined whether CSA is associated with the ALDH2*2 genotype in Japanese. METHODS AND RESULTS: The study subjects consisted of 202 patients in whom intracoronary injection of acetylcholine was performed by angiography on suspicion of CSA (119 men and 83 women; mean age, 66.2±11.4 years). They were divided into CSA (112 patients) and control groups (90 patients). ALDH2 genotyping was performed by the direct application of the TaqMan polymerase chain reaction system on dried whole blood. Clinical and laboratory data were examined using conventional methods. The frequencies of male sex, ALDH2*2 genotype carriers, alcohol flushing syndrome, tobacco smoking, and the plasma level of uric acid were higher (P<0.001, P<0.001, P<0.001, P<0.001, and P=0.007, respectively) and the plasma high-density lipoprotein cholesterol levels were lower (P<0.001) in the CSA group than in the control group. The multivariable logistic regression analysis revealed that ALDH2*2 genotype and smoking were significantly associated with CSA (P<0.001 and P=0.024, respectively). CONCLUSIONS: East Asian variant ALDH2*2 genotypes and, hence, deficient ALDH2 activity were associated with CSA in Japanese. These data support further investigation of treatment targeting aldehydes for CSA.

Alcohol flushing and positive ethanol patch test in patients with coronary spastic angina: possible role of aldehyde dehydrogenase 2 polymorphisms.

OBJECTIVE: Coronary spasm plays an important role in the pathogenesis of coronary heart disease (CHD) and angina pectoris caused by coronary spasm or coronary spastic angina (CSA) is prevalent in Japan. However, the precise mechanisms underlying coronary spasm are unclear. Alcohol intolerance is prevalent among East Asians, and we previously reported that coronary spasm could be induced by alcohol intake in CSA patients. We herein examined whether CSA is associated with alcohol intolerance in Japanese subjects. METHODS: The study subjects consisted of 80 CSA patients (57 men/ 23 women, mean age 62 ± 12) and 52 non-CSA patients (25 men/27 women, mean age 63 ± 10). The ethanol patch test (EPT) and questionnaire which evaluates flushing after ethanol intake, along with an examination of clinical features and laboratory chemistry data for CHD risk factors were done. Gender (male) and smoking were higher (p=0.007, and p=0.019, respectively) and plasma HDL cholesterol level was lower (p=0.035) in the CSA patients than in the non-CSA patients. Multivariable logistic regression analysis including age, EPT, smoking, and plasma HDL cholesterol level as independent variables revealed that positive EPT and smoking were significant predictors of CSA (p=0.011 and p=0.016, respectively). CONCLUSION: Positive EPT and alcohol flushing following alcohol intake, as well as smoking and plasma levels of HDL cholesterol, were significantly associated with CSA in Japanese patients. Therefore, alcohol ingestion as well as smoking is a significant risk factor for CSA in Japanese.

Usefulness of plasma B-type natriuretic peptide as a prognostic marker of cardiac function in senile systemic amyloidosis and in familial amyloidotic polyneuropathy.

OBJECTIVE: In senile systemic amyloidosis (SSA), a common age-related amyloidosis, wild-type transthyretin accumulates in tissues, with a primary result being cardiac dysfunction. Here, we aimed to clarify the usefulness of B-type natriuretic peptide (BNP) as a prognostic marker of cardiac function in SSA and in familial amyloidotic polyneuropathy (FAP). METHODS AND RESULTS: We studied 13 patients with severe SSA and 14 patients with FAP. SSA patients, but not FAP patients, demonstrated a significant correlation of log BNP with the echocardiographic diastolic marker E/e' ratio (r = 0.78, p < 0.01). SSA patients also showed significant correlations between log BNP and log C-reactive protein or log high-sensitive troponin T (r = 0.70, p < 0.01; r = 0.64, p < 0.05). FAP patients, however, had significant correlations between log BNP and left ventricular wall thickness (intraventricular septum thickness diastole and posterior wall thickness diastole) (r = 0.73, p < 0.01; r = 0.77, p < 0.01). The mean log BNP level in the follow-up period was significantly higher than that in the diagnostic period in SSA patients (2.65 ± 0.45 versus 2.36 ± 0.40, p < 0.01) but not in FAP patients (1.91 ± 0.56 versus 1.93 ± 0.45, p = 0.87). An especially notable phenomenon was the high plasma BNP level (≥180 pg/ml) in SSA patients. CONCLUSION: Plasma BNP levels may be a useful prognostic marker of cardiac function in SSA.

Coronary spastic angina is associated with insulin resistance - possible involvement of endothelial dysfunction.

OBJECTIVE: In this study, we examined whether coronary spastic angina (CSA) is associated with insulin resistance. BACKGROUND: There is increasing evidence that insulin resistance is associated with endothelial dysfunction. Patients with CSA show endothelial dysfunction. METHODS: The study participants include 111 CSA patients (81 men and 30 women, mean age 62±12 years) and 53 participants without CSA (24 men and 29 women, mean age 63±10 years), serving as the controls. The oral glucose tolerance test was performed, and anthropometric parameters, plasma glucose and insulin levels, lipid profiles, and other laboratory parameters were evaluated. RESULTS: Homeostasis model assessment of insulin resistance (HOMA-IR), Log HOMA-IR, the quantitative insulin sensitivity check index, the insulin sensitivity index, and insulin resistance 60-120 min after glucose load (log post-glucose-IR) were calculated as surrogate markers of insulin resistance. The number of men, the number of smokers, log post-glucose-IR, the insulin sensitivity index, and fasting plasma glucose levels were higher in CSA patients compared with controls (P=0.001, 0.001, 0.004, 0.012, and 0.013, respectively), whereas plasma high-density lipoprotein cholesterol levels were lower (P<0.001). CONCLUSION: Insulin resistance on glucose load (log post-glucose-IR), plasma high-density lipoprotein cholesterol levels, and smoking were significantly associated with CSA (r=0.225, P=0.004; r=-0.313, P<0.001; and r=0.258, P=0.001, respectively).

Suppression of primary aldosteronism and resistant hypertension by the peroxisome proliferator-activated receptor gamma agonist pioglitazone.

The peroxisome proliferator-activated receptor gamma (PPAR γ) agonists have been reported to have antiproliferative and tumor-suppressive effects. We report a case of 55-year-old man with primary aldosteronism (PA) whose hyperaldosteronism was suppressed with the PPAR γ agonist pioglitazone. He had drug-resistant hypertension, hypokalemia, and diabetes mellitus. The diagnosis of PA was confirmed by the oral sodium loading test (20.5 µg/d of urinary aldosterone) and Captopril challenge test (19.5 ng/dL of plasma aldosterone). Computed tomography imaging revealed no apparent adrenal mass. The result of the posture stimulation test was consistent with the diagnosis of idiopathic adrenal hyperplasia. On administration of pioglitazone (30 mg/d) and nifedipine (40 mg/d), hypertension and hypokalemia improved and plasma aldosterone decreased for more than 6 months. The sodium loading test done after 6 months of the administration revealed the near normal results (11.2 ng/dL of plasma aldosterone and 13.1 µg/d of urinary aldosterone). The findings indicated that pioglitazone suppressed PA.

Novel function of transthyretin in pancreatic alpha cells.

Although transthyretin (TTR) is expressed in pancreatic alpha (glucagon) cells in the islets of Langerhans, the function of TTR in pancreatic alpha cells remains unknown. In this study, by using TTR knockout (TTR KO) mice, we determined the novel role of TTR in glucose homeostasis. We demonstrated that TTR KO mice evidenced impaired recovery of blood glucose and glucagon levels. Lack of TTR induced significantly lower levels of glucagon in the islets of Langerhans. These results suggest that TTR expressed in pancreatic alpha cells may play important roles in glucose homeostasis via regulating the expression of glucagon.

Potential use of glucuronylglucosyl-ß-cyclodextrin as a novel therapeutic tool for familial amyloidotic polyneuropathy.

Transthyretin (TTR)-related familial amyloidotic polyneuropathy, which is induced by amyloidogenic transthyretin (ATTR), is characterized by systemic accumulation of amyloid fibrils. Although it is believed that protein misfolding of monomeric form of TTR is a rate-limiting step for TTR amyloid formation, no effective therapy targeting this misfolding step is available. Our recent studies revealed that cyclodextrins (CyDs), cyclic oligosaccharides composed of glucose units, might interact with TTR and prevent the protein misfolding. In this study, we focused on and elucidated the inhibitory effect of 6-O-α-(4-O-α-D-Glucuronyl)-D-glucosyl-ß-CyD (GUG-ß-CyD) on TTR amyloid formation. Tryptophan (Trp) fluorescence and (1)H-NMR spectroscopy analyses indicated that GUG-ß-CyD stabilized TTR conformation via interaction with the hydrophobic amino acids of TTR. Moreover, GUG-ß-CyD suppressed TTR deposition in transgenic rats possessing a human ATTR V30M gene in vivo. Collectively, these data indicate that GUG-ß-CyD may inhibit TTR misfolding by stabilizing its conformation, which, in turn, suppresses TTR amyloid formation.

Antibody therapy for familial amyloidotic polyneuropathy.

Although it is believed that altered conformations exposing cryptic regions are intermediary and critical steps in the mechanism of transthyretin (TTR) amyloid formation, no effective therapy targeting this step is available. In this study, to establish the antibody therapy for familial amyloidotic polyneuropathy (FAP), we generated a monoclonal anti-TTR antibody, which specifically reacts with surface epitopes of TTR (MAb ATTR) and evaluated its binding affinity and specificity for TTR amyloid fibrils. MAb ATTR showed specific binding affinity for TTR amyloid fibrils, but not for native form of TTR. Moreover, MAb ATTR indeed showed the high consistency with Congo red positive areas in tissue specimens from FAP ATTR V30M patients, indicating that MAb ATTR showed binding affinity and specificity for TTR amyloid fibrils in vitro and in vivo. MAb ATTR may have a potential to suppress TTR amyloid deposition and become a candidate for the antibody therapy for FAP.

Clinicopathological features of senile systemic amyloidosis: an ante- and post-mortem study.

Senile systemic amyloidosis is a common age-related amyloidosis that involves accumulation of wild-type transthyretin, with cardiac dysfunction being a predominant result. The importance of obtaining an accurate diagnosis of senile systemic amyloidosis has been increasingly recognized, so that novel treatments are being developed. However, the clinicopathological features of senile systemic amyloidosis remain to be completely understood. Here, we evaluated cardiac specimens from 181 consecutive post-mortem cases older than 40 years, including 6 cases of senile systemic amyloidosis, and 5 cases of familial amyloidotic polyneuropathy, which is a hereditary systemic amyloidosis caused by mutant forms of transthyretin. Furthermore, we studied ante-mortem clinicopathological findings of 11 senile systemic amyloidosis cases, in which 9 cases underwent gastrointestinal tract biopsy and/or subcutaneous tissue biopsy, at Kumamoto University Hospital. Of the autopsied cases of elderly Japanese (older than 80 years), 12% had senile systemic amyloidosis, with the percentage increasing with age. The occurrence of senile systemic amyloidosis in elderly Japanese patients was lower than that in previous reports, which suggests that a genetic background and/or environmental factor(s) may have important roles in the occurrence of senile systemic amyloidosis. Transthyretin amyloid deposits in familial amyloidotic polyneuropathy cases developed mainly in the pericardium and the surrounding muscle fascicles, whereas in cases with senile systemic amyloidosis the transthyretin amyloid deposits had a patchy plaque-like shape and developed mainly inside the ventricular wall. Biopsies from senile systemic amyloidosis patients evidenced amyloid deposits in 44% (4/9) of gastrointestinal tract and subcutaneous tissue samples combined. As myocardial biopsy may be dangerous for elderly people, the use of a combination of gastrointestinal tract and subcutaneous tissue biopsies may make diagnosis of senile systemic amyloidosis easier.

Spinal multifocal amyloidosis derived from wild-type transthyretin.

Abstract Spinal amyloidosis can occur as a part of systemic amyloidosis or as localized amyloidomas. However, the exact pathogenesis of the spinal amyloidosis remains to be fully understood. Transthyretin (TTR) is an amyloidogenic protein causing two kinds of amyloid diseases. One is senile systemic amyloidosis (SSA), which is caused by wild-type (WT) TTR and primarily affects cardiac functions. The other type is familial amyloidosis, which is mainly induced by mutated TTR. We report here the first case of multifocal spinal TTR amyloidosis derived from WT TTR with radiculomyelopathy and destructive spondylosis. The data and clinical manifestations suggest that the patient may develop SSA. Clinical manifestations of TTR-related amyloidosis may vary more than we previously thought. In spinal amyloidosis, WT TTR is one of the candidate precursor proteins for the disease.

Cyclodextrin, a novel therapeutic tool for suppressing amyloidogenic transthyretin misfolding in transthyretin-related amyloidosis.

TTR (transthyretin), a ß-sheet-rich protein, is the precursor protein of familial amyloidotic polyneuropathy and senile systemic amyloidosis. Although it has been widely accepted that protein misfolding of the monomeric form of TTR is a rate-limiting step for amyloid formation, no effective therapy targeting this misfolding step is available. In the present study, we focused on CyDs (cyclodextrins), cyclic oligosaccharides composed of glucose units, and reported the inhibitory effect of CyDs on TTR amyloid formation. Of various branched ß-CyDs, GUG-ß-CyD [6-O-α-(4-O-α-D-glucuronyl)-D-glucosyl-ß-CyD] showed potent inhibition of TTR amyloid formation. Far-UV CD spectra analysis showed that GUG-ß-CyD reduced the conformational change of TTR in the process of amyloid formation. In addition, tryptophan fluorescence and 1H-NMR spectroscopy analyses indicated that GUG-ß-CyD stabilized the TTR conformation via interaction with the hydrophobic amino acids of TTR, especially tryptophan. Moreover, GUG-ß-CyD exerted its inhibitory effect by reducing TTR deposition in transgenic rats possessing a human variant TTR gene in vivo. Collectively, these results indicate that GUG-ß-CyD may inhibit TTR misfolding by stabilizing its conformation, which, in turn, suppresses TTR amyloid formation.

Loss of functional albumin triggers acceleration of transthyretin amyloid fibril formation in familial amyloidotic polyneuropathy.

Transthyretin (TTR)-related familial amyloidotic polyneuropathy (FAP) is characterized by systemic accumulation of amyloid fibrils caused by a point mutation in the TTR gene. Despite the urgent need for alternative therapeutic strategies, the pathogenesis of FAP still remains elusive. In our study reported here, we focused on albumin, the most abundant protein in plasma, and described the role of albumin in the TTR amyloid-formation process. Patients with FAP evidenced significantly decreased serum albumin levels as the disease progressed. Biacore analysis showed that albumin had a binding affinity for TTR and exhibited higher affinity for TTR amyloid than native TTR. Albumin functioning as an antioxidant effectively suppressed TTR amyloid formation. In patients with FAP, albumin was significantly oxidized as the disease progressed. Moreover, loss of functional albumin accelerated TTR deposition in analbuminemic rats possessing a human variant TTR gene. Taken together, these results indicate that albumin may have an inhibitory role in the TTR amyloid-formation process.

Transmission of circulating cell-free AA amyloid oligomers in exosomes vectors via a prion-like mechanism.

Recent studies clearly demonstrated that several types of pathogenic amyloid proteins acted as agents that could transmit amyloidosis by means of a prion-like mechanism. Systemic AA amyloidosis is one of the most severe complications of chronic inflammatory disorders, particularly rheumatoid arthritis. It is well known that, similar to an infectious prion protein, amyloid-enhancing factor (AEF) acts as a transmissible agent in AA amyloidosis. However, how AEF transmits AA amyloidosis in vivo remained to be fully elucidated. In the present study, we focused on finding cell-free forms of AEF and its carriers in circulation by using the murine transfer model of AA amyloidosis. We first determined that circulating cell-free AEF existed in blood and plasma in mice with systemic AA amyloidosis. Second, we established that plasma exosomes containing AA amyloid oligomers derived from serum amyloid A had AEF activity and could transmit systemic AA amyloidosis via a prion-like mechanism. These novel findings should provide insights into the transmission mechanism of systemic amyloidoses.