Transmitral E/A ratio decreases in association with abdominal fat accumulation in patients with impaired glucose tolerance or mild diabetes without left ventricular hypertrophy

An abnormal left ventricular (LV) diastolic function is an early sign of diabetic cardiomyopathy, which is characterized by an impaired diastolic and/or systolic function of the left ventricle in the absence of ischemic, valvular, or hypertensive heart disease, and serves as a marker of cardiovascular risk. However, it is unclear whether LV diastolic abnormalities can be detected in patients with impaired glucose tolerance (IGT) or mild diabetes without LV hypertrophy (LVH). We examined echocardiographic data from 92 consecutive Japanese patients aged 45-79 years with or without IGT or mild diabetes in the absence of LVH. Impaired glucose tolerance or mild diabetes was defined as the presence of one or more of the following criteria: fasting plasma glucose >110 mg/dl, hemoglobin A1c >5.6%, homeostasis model assessment ratio >1.73, or the taking of oral antihyperglycemic drugs. Left ventricular hypertrophy was defined as an LV mass index (LVMI) >116 g/m(2) in men and >104 g/m(2) in women. Patients with ischemic, valvular, or hypertensive heart disease were excluded. The age, blood pressure, heart rate, and LVMI were similar between patients with (IGT/DM group, n = 43) and without IGT or mild diabetes (non-IGT/DM group, n = 49), whereas the body mass index and waist circumference (WC) were greater in the IGT/DM compared to the non-IGT/DM group (P < 0.05 and P < 0.001, respectively). The transmitral E/A ratio was lower and the deceleration time longer in the IGT/DM than in the non-IGT/DM group (both P < 0.05). Stepwise regression analysis revealed that age and WC were independent determinants of the E/A ratio. In conclusion, diastolic abnormalities without LVH can be detected in Japanese patients with IGT or mild diabetes. The E/A ratio decreases in association with abdominal fat accumulation.

Soluble VEGF receptor-2 is increased in sera of subjects with metabolic syndrome in association with insulin resistance

OBJECTIVE

Metabolic syndrome (MetS) is associated with impaired angiogenesis. Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis through binding to its specific receptor, VEGF receptor-2 (VEGFR-2), whereas the expression of VEGF and VEGFR-2 in the myocardium of insulin-resistant rats is down-regulated. Soluble VEGF receptor-1 (sVEGFR-1) and -2 (sVEGFR-2) have been reported to inhibit angiogenesis both in vitro and in vivo. However, the balance between circulating levels of VEGF and its soluble receptors, which may reflect and/or affect cardiovascular VEGF signaling, in subjects with MetS is unknown.

METHODS AND RESULTS

We carried out a cross-sectional study including 272 consecutive, apparently healthy subjects who were not receiving any drugs. Plasma levels of VEGF and serum levels of its soluble receptors were determined using enzyme-linked immunosorbent assays. VEGF and sVEGFR-1 levels did not differ between subjects with and those without MetS. However, sVEGFR-2 levels were significantly increased in MetS compared with non-MetS subjects. Stepwise regression analysis revealed that HOMA-IR was the strongest independent determinant of the sVEGFR-2 level. Accordingly, the mean sVEGFR-2 levels increased in proportion to both the accumulation of components of MetS and quartile of HOMA-IR. Interestingly, multiple regression analyses revealed that independent determinants of VEGF were the body mass index and blood pressure, whereas, in contrast, those of sVEGFR-2 were HOMA-IR and high-sensitivity C-reactive protein.

CONCLUSIONS

The correlation of sVEGFR-2 with insulin resistance supports the need for further investigations to define the clinical utility and predictive value of serum sVEGFR-2 levels in cardiovascular dysfunction in MetS.

Evaluation of the cardio-ankle vascular index, a new indicator of arterial stiffness independent of blood pressure, in obesity and metabolic syndrome

Aortic stiffness is predictive of cardiovascular diseases (CVD) and mortality in lifestyle-related diseases. The cardio-ankle vascular index (CAVI), a new index of arterial stiffness, was recently developed by measuring of pulse wave velocity (PWV) and blood pressure (BP). CAVI is adjusted for BP based on stiffness parameter beta and is less influenced by BP, suggesting its superiority over brachial-ankle PWV (baPWV). However, there are currently no reports on the usefulness of CAVI as an atherogenic index in obesity and metabolic syndrome (MS). Among the 325 obese Japanese outpatients enrolled in the multi-centered Japan Obesity and Metabolic Syndrome Study, 216 patients (67%) met the criteria of MS according to the modified National Cholesterol Education Program-Adult Treatment Panel III. CAVI values were significantly higher in MS than in non-MS patients, whereas there was no significant difference in body mass index, total cholesterol, and low-density lipoprotein-cholesterol between both groups. CAVI values were weakly correlated with BP but closely correlated with the severity of MS and MS-related parameters such as hypoadiponectinemia, relative to baPWV. Furthermore, weight-reduction therapy through diet and exercise over a 3-month period significantly decreased CAVI values in parallel with increasing adiponectin. This study demonstrates for the first time that CAVI is a good indicator of arterial stiffness. It is closely correlated with the severity of MS and CVD risks in obesity and independent of BP, and is thus superior to baPWV. Therefore, the determination of arterial stiffness by CAVI may be useful for evaluating and managing the CVD risks of MS patients.

Unfavorable blood rheology is closely associated with arterial stiffness in obese patients

Little information on the relationship between blood rheology and atherosclerosis indicators in obese patients is available. We examined blood rheology as assessed by the blood passage time (BPT) with the microchannel method in 109 obese patients. BPT was correlated well with the extent of each metabolic syndrome component. A multivariate regression analysis revealed that the independent contributors to BPT were pulse-wave velocity, an index of arterial stiffness, body mass index and red blood cell. Furthermore, weight reduction intervention significantly decreased BPT. Assessment of rheology may be associated with pulse-wave velocity, and useful to manage obese patients.

Effects of risedronate or alfacalcidol on bone mineral density, bone turnover, back pain, and fractures in Japanese men with primary osteoporosis: results of a two-year strict observational study

Although osteoporosis in men is already a major public health problem, there is still a dearth of data about the effects of risedronate in male osteoporosis, especially in Japanese with primary osteoporosis. Therefore, the objective of our study was to investigate the effects of risedronate on bone mineral density (BMD), bone turnover, back pain, and fractures in these patients prospectively for two years (at baseline, three months, six months, twelve months, and twenty-four months) both longitudinally and compared with those of alfacalcidol. The subjects enrolled for this study were 66 Japanese male patients with untreated primary osteoporosis (mean age 63.52 +/- 8.7 years), who were divided into two groups (44 with risedronate and 22 with alfacalcidol). We measured BMD by dual energy X-ray absorptiometry at three sites-the lumbar spine, femoral neck, and distal radius. Risedronate treatment significantly increased BMD at the lumbar spine and at the femoral neck, reduced bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx), and reduced back pain, both longitudinally and compared with alfacalcidol treatment. We observed a lower rate of incident fracture in risedronate users. However, multiple logistic regression analysis revealed that this trend was not statistically significant, possibly because of the small number of patients enrolled. These potentially beneficial effects of risedronate on bone in male patients with primary osteoporosis suggest the possibility that osteoporosis should be treated with risedronate regardless of gender in order to effectively prevent subsequent osteoporotic fractures.

Up-regulated expression of microRNA-143 in association with obesity in adipose tissue of mice fed high-fat diet

MicroRNAs (miRNAs) are short non-coding RNA that post-transcriptionally regulates gene expression. miR-143 has been proposed to play a role in the differentiation of adipocytes in culture. However, the mechanism regulating the expression of miR-143 in adult adipose tissue during the development of obesity in vivo is unknown. Here in, we showed that the expression of miR-143 in the mesenteric fat was up-regulated in mice fed a high-fat diet. Increased miR-143 expression was associated with an elevated body weight and mesenteric fat weight. Furthermore, miR-143 levels were closely correlated with expression levels of adipocyte differentiation markers such as PPARgamma and aP2 as well as plasma levels of leptin, one of the important adipocytokines involved in insulin resistance. These findings provide the first evidence for the up-regulated expression of miR-143 in the mesenteric fat of high-fat diet-induced obese mice, which might contribute to the regulated expression of adipocyte genes involved in the pathophysiology of obesity.

A novel oxidized low-density lipoprotein marker, serum amyloid A-LDL, is associated with obesity and the metabolic syndrome

BACKGROUND

The putative association between the novel oxidized low-density lipoprotein markers, serum amyloid A-LDL (SAA-LDL) and alpha1-antitrypsin-LDL (AT-LDL), and obesity and the metabolic syndrome (MetS) has not been previously studied. In the present report, we investigated the levels of SAA-LDL and AT-LDL in relation to the components of the MetS. We also assessed the effect of weight reduction therapy on serum SAA-LDL and AT-LDL levels among obese subjects.

METHODS

The study population included 421 obese Japanese outpatients (185 men and 236 women, mean age: 51.1 years) enrolled in the multicenter Japan Obesity and Metabolic Syndrome Study (JOMS). The novel oxidized low-density lipoprotein markers, serum SAA-LDL and AT-LDL, were measured in all participants.

RESULTS

Circulating SAA-LDL levels were independently associated with the presence and the number of components of the MetS. SAA-LDL levels were also significantly and independently correlated with high-sensitivity C-reactive protein. Notably, successful weight reduction resulted in a significant decrease in circulating SAA-LDL concentrations. Levels of AT-LDL were not associated with the MetS.

CONCLUSIONS

We documented, for the first time, that serum SAA-LDL levels correlate positively with the number of components of the MetS and weight reduction. Whether SAA-LDL may be involved in the pathophysiology of MetS and atherosclerosis deserves further investigation.

Effects of Bupleurum scorzoneraefolium, Bupleurum falcatum, and saponins on nephrotoxic serum nephritis in mice

ETHNOPHARMACOLOGICAL SIGNIFICANCE

Bupleuri radix is a commonly prescribed Oriental herbal medicine containing extracts of different Bupleuri species. We wished to determine whether two of these species, Bupleurum scorzoneraefolium and Bupleurum falcatum, or their active ingredients, saikosaponins a, c, and d, could prevent the development of immune-complex nephritis in nephrotoxic serum treated mice.

MATERIALS AND METHODS

Immune-complex nephritis was created in C57BL/6 mice by administration of nephrotoxic serum containing anti-basement membrane antibodies. Mice were next given one of five treatments: Bupleurum scorzoneraefolium, Bupleurum falcatum, saikosaponin a, saikosaponin c, or saikosaponin d. Proteinuria, blood urea nitrogen, creatinine, and renal histological changes were then examined.

RESULTS

Saikosaponin c almost completely prevented the development of nephritis, although immune-complex deposition was not affected. Bupleurum falcatum and saikosaponin d had a significant, although lesser effect, and Bupleurum falcatum and saikosaponin a showed no effect.

CONCLUSIONS

The mechanism of action of saikosaponin c and the reasons for the difference between the two bupleuri species should be investigated further in order to find the best way to utilize the therapeutic effect of Bupleuri radix on nephritis.

The cell death machinery controlled by Bax and Bcl-XL is evolutionarily conserved in Ciona intestinalis

Bax and Bcl-XL are key regulators of apoptosis in mammals. Here we report the functional characterization of two Bcl-2 homologues, ciBax and ciBcl-XL, in a basal invertebrate-chordate ascidian Ciona intestinalis. CiBax is a Ciona homologue of the BH1-3 pro-apoptotic protein Bax, whereas ciBcl-XL is a Bcl-XL-like anti-apoptotic protein. Molecular modeling analysis showed that ciBax and ciBcl-XL share both sequence and structural similarities to human Bax and Bcl-XL, respectively. Like their human counterparts, ciBax could form a homodimer or oligomers as well as heterodimerize with ciBcl-XL, and overexpression of ciBax caused apoptosis that could be attenuated by ciBcl-XL. Mutagenesis studies showed that the BH3 domain of ciBax is critical for its cell death-inducing function and also for its interaction with ciBcl-XL. In Ciona embryos, ectopic expression of ciBax but not its BH3 deletion mutant resulted in cell dissociation and apoptosis after late gastrula stage of embryonic development. Moreover, not only wild type ciBcl-XL but also a mutant ciBcl-XL(F101V), which is unable to interact with ciBax, could block cell dissociation and developmental deficit in Ciona embryos induced by overexpression of ciBax. Taken together, these findings suggest that functional homologues of both the BH1-3 death effector Bax and the pro-survival Bcl-XL exist in sea squirt Ciona intestinalis, and they control the cell death machinery independent of their heterodimerization.

Efficacy of combined treatment with raloxifene and alfacalcidol on bone density and biochemical markers of bone turnover in postmenopausal osteoporosis

Because both raloxifene (RLX) and alfacalcidol (ALF) have been established as therapeutic agents for osteoporosis, it is tempting to speculate that the combination therapy of RLX and ALF might provide benefits over that of either one alone. However, the efficacy of the combination therapy has not been reported yet. The purpose of this study was thus to assess the efficacy of the combination therapy on bone mineral density (BMD) and bone turnover in patients with postmenopausal osteoporosis. Sixty postmenopausal patients (mean age 71.62 +/- 9.9 years) with untreated osteoporosis were selected for this study, and were randomly divided into two groups by therapeutic regimen. Group A consisted of 28 patients treated with RLX plus ALF, while Group B consisted of 32 patients with RLX alone. Among them, 20 in group A and 22 in group B completed this study. Contrary to our expectations, at either 6 months or 12 months after the initiation of treatment, RLX plus ALF did not increase BMD at any of the skeletal sites measured, including lumbar spine, femur, and radius, nor did it reduce bone-specific alkaline phosphatase or N-terminal telopeptide of type I collagen more than RLX alone. Our results do not support the hypothesis that the combination therapy of RLX and ALF exerts more beneficial effects on bone compared than with RLX alone. However, it still remains unclear from this study whether the combination therapy of RLX and ALF is more efficacious in preventing fractures compared with RLX alone. Further studies are needed to clarify these issues.

Association between baseline values of bone turnover markers and bone mineral density and their response to raloxifene treatment in Japanese postmenopausal women with osteoporosis

It has been well established that raloxifene improves bone turnover, increases bone mineral density (BMD), and reduces the risk of fractures. However, it remains obscure which patients are more likely to respond to treatment with raloxifene in patients with postmenopausal osteoporosis. The purpose of this study was to investigate associations between baseline values of BMD and bone turnover markers (BTMs) and changes of those values after 1-year treatment with raloxifene. Sixty-eight Japanese postmenopausal women with untreated osteoporosis were selected for this study, among whom 58 patients (mean age 70.40 +/- 9.2 years) completed this study. Lower baseline values of BMD at the lumbar spine, the femoral neck, and the distal radius were significantly correlated with greater increases of BMD at those corresponding sites after 1-year treatment with raloxifene. On the other hand, higher baseline values of bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx) were significantly correlated with greater reductions of BAP and NTx, respectively, after 1-year treatment with raloxifene. Although longer and larger studies with fracture endpoints are needed, our findings suggest that baseline values of BMD and BTMs can be used to predict subsequent skeletal response to raloxifene therapy in Japanese postmenopausal women with osteoporosis.

Increased bone turnover in patients with hypercholesterolemia

Osteoporosis has been linked with arteriosclerotic vascular diseases, suggesting that hypercholesterolemia or dyslipidemia may be a common pathogenetic factor underlying these diseases. However, little is known about the relationship between osteoporosis and hypercholesterolemia. The purpose of this study was, therefore, to investigate the effects of hypercholesterolemia upon bone metabolism, by measuring bone turnover markers in hypercholesterolemic patients. This study included 281 Japanese patients with hypercholesterolemia, and 267 control subjects. Serum bone-specific alkaline phosphatase (BAP) of the patients was significantly higher than that of the controls in women. Serum N-terminal telopeptide of type I collagen (NTx) of the patients was significantly higher than that of the controls in both men and women. In addition, both BAP and NTx in men showed a significantly negative correlation with high density lipoprotein cholesterol (HDL-C). On the other hand, in women, both BAP and NTx showed a significantly positive correlation with total cholesterol and low density lipoprotein cholesterol (LDL-C). These results indicate increased bone turnover in hypercholesterolemic or dyslipidemic patients regardless of gender, and suggest the importance of treating hypercholesterolemia or dyslipidemia in order to prevent not only arteriosclerotic complications but also osteoporotic bone loss and subsequent fractures.

Three-month changes in bone turnover markers and bone mineral density response to raloxifene in Japanese postmenopausal women with osteoporosis

It has been well established that raloxifene (RLX) improves bone turnover, increases bone mineral density (BMD), and reduces the risk of fractures. However, it remains obscure how to monitor the therapeutic effects of RLX, while numerous clinical trials for other antiresorptive agents have suggested that greater short-term reductions of bone turnover markers (BTMs) can predict greater increases in BMD and greater reduction in risk of future fractures. The purpose of this study was to investigate associations between short-term reductions of BTMs and subsequent changes of BMD after 1-year treatment with RLX. Seventy-three Japanese postmenopausal women with untreated osteoporosis were selected for this study. Reductions in BTMs [bone-specific alkaline phosphatase (BAP) or serum N-terminal telopeptide of type I collagen (NTx)] after 3 months did not correlate with increases of BMD at any major sites (lumbar spine, femoral neck, total neck, and distal 1/3 radius) either after 6 months or after 12 months. Our results suggest that short-term reductions or 3-month reductions of BTMs with RLX treatment cannot be used to predict increases of BMD. However, this does not directly mean that short-term reductions or 3-month reductions of BTMs with RLX treatment cannot be used to predict risk reduction of future fractures or the ultimate effects of RLX on bone. Further studies with fracture endpoints in longer observation and larger number of patients are warranted to establish how to monitor the therapeutic effects of RLX or early identification of responders or nonresponders to RLX treatment.

Efficacy of risedronate in Japanese male patients with primary osteoporosis

OBJECTIVE

Although osteoporosis in men previously was relatively neglected, bisphosphonates have been strongly suggested as potent therapeutic agents. However, there are few studies on the effects of risedronate in male osteoporosis, especially in Japanese with primary osteoporosis. The aim of our study was to prospectively evaluate the effects of risedronate on bone mineral density (BMD) and bone turnover in Japanese male patients.

METHODS

According to the therapeutic regimen, the subjects were divided into two groups (group A, 22 with risedronate; group B, 10 without risedronate). During a one-year study duration, we measured bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx) every 3 months, and BMD at 7 sites by dual-energy X-ray absorptiometry every 6 months.

PATIENTS

The subjects were 32 Japanese male patients with untreated primary osteoporosis.

RESULTS

In group A, but not in group B, BMD was significantly increased at the lumbar spine both at 6 months and 12 months, and at the femoral neck at 12 months, compared with baseline. Likewise, in group A, but not in group B, both BAP and NTx were significantly decreased at all time points measured (3 months, 6 months, and 12 months), compared with baseline.

CONCLUSION

These results confirmed the beneficial effects of risedronate upon increasing BMD and reducing bone turnover markers in Japanese male patients with primary osteoporosis, comparable to those previously reported in postmenopausal patients with osteoporosis.

Expression of a novel 90-kDa protein, Lsd90, involved in the metabolism of very long-chain fatty acid-containing phospholipids in a mitosis-defective fission yeast mutant

The fission yeast lsd1/fas2 strain carries a temperature-sensitive mutation of the fatty-acid-synthase alpha-subunit, exhibiting an aberrant mitosis lsd phenotype, with accumulation of very-long-chain fatty-acid-containing phospholipid (VLCFA-PL). A novel 90-kDa protein, Lsd90 (SPBC16E9.16c), was found to be newly expressed in small particle-like structures in lsd1/fas2 cells under restrictive conditions. Two mismatches leading to a double frame shift were found between the sequences of the lsd90(+) gene registered in the genomic database and the sequences determined experimentally at the amino acid, cDNA and genomic DNA levels. Unexpectedly, overexpression and disruption of the lsd90(+) gene in either lsd1/fas2 or wild-type cells did not affect either cell growth or expression of the lsd phenotype. The amounts of VLCFA-PL that accumulated in lsd90-overexpressing lsd1/fas2 cells were significantly lower than those in lsd1/fas2 cells, suggesting the involvement of Lsd90 in the metabolism of VLCFA-PL.

Clinical significance of 1-year treatment with raloxifene on bone and lipid metabolism in Japanese postmenopausal women with osteoporosis

It has been well established that raloxifene (RLX) has beneficial effects on bone primarily in Caucasian women. However, to date, there is a dearth of data for Japanese postmenopausal women. In this study, we prospectively evaluated the effects of RLX on bone and lipid metabolism in fifty Japanese postmenopausal patients with untreated osteoporosis. We measured bone mineral density (BMD) by dual-energy X-ray absorptiometry at 7 sites including the lumbar spine, femoral neck, and distal radius. BMD was significantly increased at the lumbar spine both at 6 months and at 12 months compared with at baseline (p<0.01 for both), although the possibility could not be completely excluded that this increase may be partly explained by an apparent increase induced by degenerative changes in lumbar vertebrae since we had no control subjects to compare and be more certain of the findings in this study. Both bone-specific alkaline phosphatase (BAP) and serum N-terminal telopeptide of type I collagen (NTx) significantly decreased both at 6 months (p<0.01 for both) and at 12 months (p<0.01 for both) compared with at baseline, but not below the lower limit of the reference value. Total cholesterol and low-density lipoprotein cholesterol were significantly improved while triglycerides and high-density lipoprotein cholesterol were unaltered. Although longer and larger studies with fracture endpoints are needed to draw definite conclusions, our findings suggest the favorable effects of RLX on bone and lipid metabolism in Japanese postmenopausal women with osteoporosis as in Caucasian women.